Deleting 'irrational' responses from discrete choice experiments: a case of investigating or imposing preferences? Random Regret-Based Discrete-Choice Modelling: An Application to Healthcare Understanding the impact of economic evidence on clinical decision making: a discrete choice experiment in cardiology. Valuing SF-6D Health States Using a Discrete Choice Experiment A Closer Look at Decision and Analyst Error by Including Nonlinearities in Discrete Choice Models: Implications on Willingness-to-Pay Estimates Derived from Discrete Choice Data in Healthcare Evaluating Health Workers' Potential Resistance to New Interventions: A Role for Discrete Choice Experiments Does attribute framing in discrete choice experiments influence willingness to pay? Results from a discrete choice experiment in screening for colorectal cancer. Using qualitative methods for attribute development for discrete choice experiments: issues and recommendations. Does the Inclusion of a Cost Attribute Result in Different Preferences for the Surgical Treatment of Primary Basal Cell Carcinoma? The Monetary Value of Informal Care: Obtaining Pure Time Valuations Using a Discrete Choice Experiment Public preferences for establishing nephrology facilities in Greenland: estimating willingness-to-pay using a discrete choice experiment Eliciting health state utilities for Dupuytren’s contracture using a discrete choice experiment Prescriber preferences for behavioural economics interventions to improve treatment of acute respiratory infections: a discrete choice experiment Comparison of tools for assessing the methodological quality of primary and secondary studies in health technology assessment reports in Germany How does patients' quality of life guide their preferences regarding aspects of asthma therapy?: a patient-preference study using discrete-choice experiment methodology. An empirical comparison of methods for analyzing correlated data from a discrete choice survey to elicit patient preference for colorectal cancer screening Good practices for real‐world data studies of treatment and/or comparative effectiveness: Recommendations from the joint ISPOR‐ISPE Special Task Force on real‐world evidence in health care decision making Women’s preferences for childbirth experiences in the Republic of Ireland; a mixed methods study [Principles of clinical pharmacology]. General practitioners' preferences for the organisation of primary care: a discrete choice experiment. Improving the reporting of public health intervention research: advancing TREND and CONSORT. Driving up the Quality and Relevance of Research Through the Use of Agreed Core Outcomes Citizen Participation in Patient Prioritization Policy Decisions: An Empirical and Experimental Study on Patients' Characteristics The impact of cash transfers on social determinants of health and health inequalities in Sub-Saharan Africa: a systematic review protocol Online eLearning for undergraduates in health professions: A systematic review of the impact on knowledge, skills, attitudes and satisfaction Systematic reviews in public health: old chestnuts and new challenges. An international registry of systematic-review protocols Study designs and analytic strategies for environmental and policy research on obesity, physical activity, and diet: recommendations from a meeting of experts. Risk of bias in randomised controlled trials of health behaviour change interventions: Evidence, practices and challenges Patients’ view of retail clinics as a source of primary care: Boon for nurse practitioners? Patient preferences for osteoporosis in Spain: a discrete choice experiment Barriers to successful implementation of care in home haemodialysis (BASIC-HHD):1. Study design, methods and rationale A Systematic Review of The Impact of Improved Housing Interventions on Health In Low And Middle Income Tropical Settings. Using discrete choice experiment to elicit doctors' preferences for the report card design of diabetes care in Taiwan - a pilot study. Reporting quality of life in clinical trials: a CONSORT extension Validation of the Dominant Sequence Paradigm and Role of Dynamic Contrast-enhanced Imaging in PI-RADS Version 2. Economic Analysis of Health Care Technology: A Report on Principles
Investigation of the ' rationality ' of responses to discrete choice experiments ( DCEs ) has been a theme of research in health economics . Responses have been deleted from DCEs where they have been deemed by research ers to ( a ) be ' irrational ' , defined by such studies as failing tests for non-satiation , or ( b ) represent lexicographic preferences . This paper outlines a number of reasons why deleting responses from DCEs may be inappropriate after first review ing the theory underpinning rationality , highlighting that the importance placed on rationality depends on the approach to consumer theory to which one ascribes . The aim of this paper is not to suggest that all preferences elicited via DCEs are rational . Instead , it is to suggest a number of reasons why it may not be the case that all preferences labelled as ' irrational ' are indeed so . Hence , deleting responses may result in the removal of valid preferences ; induce sample selection bias ; and reduce the statistical efficiency and power of the estimated choice models . Further , evidence suggests r and om utility theory may be able to cope with such preferences . Finally , we discuss a number of implication s for the design , implementation and interpretation of DCEs and recommend caution regarding the deletion of preferences from stated preference experiments Background A new modelling approach for analysing data from discrete-choice experiments ( DCEs ) has been recently developed in transport economics based on the notion of regret minimization-driven choice behaviour . This so-called R and om Regret Minimization ( RRM ) approach forms an alternative to the dominant R and om Utility Maximization ( RUM ) approach . The RRM approach is able to model semi-compensatory choice behaviour and compromise effects , while being as parsimonious and formally tractable as the RUM approach . Objectives Our objectives were to introduce the RRM modelling approach to healthcare-related decisions , and to investigate its usefulness in this domain . Methods Using data from DCEs aim ed at determining valuations of attributes of osteoporosis drug treatments and human papillomavirus ( HPV ) vaccinations , we empirically compared RRM models , RUM models and Hybrid RUM – RRM models in terms of goodness of fit , parameter ratios and predicted choice probabilities . Results In terms of model fit , the RRM model did not outperform the RUM model significantly in the case of the osteoporosis DCE data ( p = 0.21 ) , whereas in the case of the HPV DCE data , the Hybrid RUM – RRM model outperformed the RUM model ( p < 0.05 ) . Differences in predicted choice probabilities between RUM models and ( Hybrid RUM- ) RRM models were small . Derived parameter ratios did not differ significantly between model types , but trade-offs between attributes implied by the two models can vary substantially . Conclusion Differences in model fit between RUM , RRM and Hybrid RUM – RRM were found to be small . Although our study did not show significant differences in parameter ratios , the RRM and Hybrid RUM – RRM models did feature considerable differences in terms of the trade-offs implied by these ratios . In combination , our results suggest that RRM and Hybrid RUM – RRM modelling approach hold the potential of offering new and policy-relevant insights for health research ers and policy makers The present study aims to evaluate the impact of  cost-effectiveness information  on clinical decision making using discrete choice experiment ( DCE ) methodology . Data were collected through a self-completed question naire  administered to Italian cardiologists in June 2007 ( n = 129 respondents , 1143 observations ) . The question naire asked clinicians to make choices between paired scenarios , across which three key dimensions were identified and varied : ( 1 ) quality of clinical evidence , ( 2 ) size of health gain ( reduction of relative and absolute risk ) , and ( 3 ) economic impact ( incremental cost-effectiveness ratio ) . A r and om effects probit model was used to estimate clinicians ' preferences for the different dimensions , while the heterogeneity of preferences was tested in a model with interaction terms . Dominance tests were used to assess the consistency of responses . The results indicate that Italian cardiologists regard economic impact ( cost-effectiveness ) as an important factor in their decision making . Economic evidence is valued more highly among clinicians with a higher self-assessed level of knowledge regarding economic evaluation techniques , as well as among younger professionals ( age<45 ) . While relevant study limitations should be acknowledged , our results suggest that DCEs can be used to elicit clinicians ' decision-making criteria and to inform the allocation of re sources for future research in a logical manner . Italian cardiologists appear to take  cost-effectiveness information into account when deciding whether to use new treatments Background . SF-6D utility weights are conventionally produced using a st and ard gamble ( SG ) . SG-derived weights consistently demonstrate a floor effect not observed with other elicitation techniques . Recent advances in discrete choice methods have allowed estimation of utility weights . The objective was to produce Australian utility weights for the SF-6D and to explore the application of discrete choice experiment ( DCE ) methods in this context . We hypothesized that weights derived using this method would reflect the largely monotonic construction of the SF-6D . Methods . We design ed an online DCE and administered it to an Australia-representative online panel ( n = 1017 ) . A range of specifications investigating nonlinear preferences with respect to additional life expectancy were estimated using a r and om-effects probit model . The preferred model was then used to estimate a preference index such that full health and death were valued at 1 and 0 , respectively , to provide an algorithm for Australian cost-utility analyses . Results . Physical functioning , pain , mental health , and vitality were the largest drivers of utility weights . Combining levels to remove illogical orderings did not lead to a poorer model fit . Relative to international SG-derived weights , the range of utility weights was larger with 5 % of health states valued below zero . Conclusion s. DCEs can be used to investigate preferences for health profiles and to estimate utility weights for multi-attribute utility instruments . Australian cost-utility analyses can now use domestic SF-6D weights . The comparability of DCE results to those using other elicitation methods for estimating utility weights for quality -adjusted life-year calculations should be further investigated Background Most research ers in health economics cite r and om utility theory ( RUT ) when analysing discrete choice experiments ( DCEs ) . Under RUT , the error term is associated with the analyst ’s inability to properly capture the true choice processes of the respondent as well as the inconsistency or mistakes arising from the respondent themselves . Under such assumptions , it st and s to reason that analysts should explore more complex nonlinear indirect utility functions , than currently used in healthcare , to strive for better estimates of preferences in healthcare . Objective To test whether complex indirect utility functions decrease error variance for models that either implicitly ( i.e. the multinomial logit ( MNL ) model ) or explicitly ( i.e. entropy multinomial logit ( EMNL ) model ) account for error variance in health(care)-related DCEs ; and to determine the impact of complex indirect utility functions on willingness-to-pay ( WTP ) measures . Methods Using data from DCEs aim ed at healthcare-related decisions , we empirically compared ( 1 ) complex and simple indirect utility specifications in terms of goodness of fit , ( 2 ) their impact on WTP measures , including confidence intervals ( CIs ) based on the Delta method , the Krinsky and Robb-procedure , and Bootstrapping , and ( 3 ) MNL and EMNL model results . Results Complex indirect utility functions had a better model fit than simple specifications ( p < 0.05 ) . WTP estimates were quite similar across alternative specifications . The Delta method produced the most narrow CIs . The EMNL model showed that respondents apply simplifying strategies when answering DCE questions . Conclusion Complex indirect utility functions reduce error arisen from research ers , which can have important implication s for measures in healthcare such as the WTP , whereas EMNL provides insights into the behaviour of respondents when answering DCEs . Underst and ing how respondents answer DCE questions may allow research ers to construct DCEs that minimise scale differences , so that the decision error made across respondents is more homogeneous and therefore taken out as additional noise in the data . Hence , better estimates of preferences in healthcare can be provided Background The currently recommended approach for preventing malaria in pregnancy ( MiP ) , intermittent preventive treatment with sulphadoxine-pyrimethamine ( SP-IPT ) , has been question ed due to the spread of resistance to SP . Whilst trials are underway to test the efficacy of future alternative approaches , it is important to start exploring the feasibility of their implementation . Methods and Findings This study uses a discrete choice experiment ( DCE ) method to assess the potential resistance of health workers to changing strategies for control of MiP. In Ashanti region in Ghana , 133 antenatal clinic health workers were presented with 16 choice sets of two alternative policy options , each consisting of a bundle of six attributes representing certain clinical guidelines for controlling MiP ( type of approach and drug used ) , possible associated maternal and neo-natal outcomes , workload and financial incentives . The data were analysed using a r and om effects logit model . Overall , staff showed a preference for a curative approach with pregnant women tested for malaria parasites and treated only if positive , compared to a preventive approach ( OR 1.6 ; p = 0.001 ) . Increasing the incidence of low birth weight or severe anaemia by 1 % would reduce the odds of preferring an approach by 18 % and 10 % respectively . Midwives were more resistant to potential changes to current guidelines than lower-level cadres . Conclusions In Ashanti Region , resistance to change by antenatal clinic workers from a policy of SP-IPT to IST would generally be low , and it would disappear amongst midwives if health outcomes for the mother and baby were improved by the new strategy . DCEs are a promising approach to identifying factors that will increase the likelihood of effective implementation of new interventions immediately after their efficacy has been proven OBJECTIVE Recent review s of discrete choice methodology identified method ological issues warranting further exploration , including the issue of " framing . " The objective of this study was to conduct a method ological exploration of the effect of attribute framing on marginal rates of substitution ( MRS ) , including willingness to pay ( WTP ) from a discrete choice experiment ( DCE ) , within the context of colorectal cancer screening preferences . METHODS The survey , a fractional factorial design of a two-alternative , unlabeled experiment , was mailed to a sample of 1920 subjects in NSW , Australia . Participants were r and omized to one of four alternative " frames " of information . Attributes included : accuracy of the test for finding cancers , accuracy of the test for finding large polyps , how good the test is at saying you do n't have cancer , cost , dietary and medication restrictions and sample collection . A mixed logit model was used to estimate preferences ; MRS between attributes , including WTP , was calculated . RESULTS A total of 1157 surveys from 1920 ( 60.2 % ) were returned . Accuracy of the test for finding cancer was most likely to influence choice of test , followed by accuracy of the test for finding large polyps . Under some circumstances , framing of the attributes ( e.g. , cancers found vs. cancers missed ) influenced the relative importance of attributes . Attribute framing significantly influenced estimates of WTP , and benefit : harm trade-offs that were calculated from MRS . CONCLUSIONS Attribute framing can influence willingness to pay and benefit : harm trade-offs from DCEs . Appropriate design and analysis methods should be explored to further characterize the influence and extent of framing in discrete choice studies Attribute generation for  discrete choice experiments ( DCEs ) is often poorly reported , and it is unclear whether this element of research is conducted rigorously . This paper explores issues associated with developing attributes for DCEs  and contrasts different qualitative approaches . The paper draws on eight studies , four developed attributes for measures , and four developed attributes  for more ad hoc policy questions . Issues that have become apparent through these studies include the following : the theoretical framework for r and om utility theory and the need for attributes that are neither too close to the latent construct nor too intrinsic to people 's personality ; the need to think about attribute development as a two-stage process involving conceptual development followed by refinement of language to convey the intended meaning ; and the difficulty in resolving tensions inherent in the reductiveness of condensing complex and nuanced qualitative findings into precise terms . The comparison of alternative qualitative approaches suggests that the nature of data collection will depend both on the characteristics of the question ( its sensitivity , for example ) and the availability of existing qualitative information . An iterative , constant comparative approach to analysis is recommended . Finally , the paper provides a series of recommendations for improving the reporting of this element of DCE studies Background : Nowadays , an increasing number of discrete-choice experiments ( DCEs ) incorporate cost as an attribute . However , the inclusion of a cost attribute , particularly within collectively funded healthcare systems , can be challenging because health services or goods are generally not traded in a market situation and individuals are not used to paying for a service or a good at the point of consumption . Objective : To examine whether the inclusion of a cost attribute in a DCE results in different preferences regarding a surgical treatment  for primary basal cell carcinoma ( BCC ) compared with a DCE without a cost attribute . Methods : A r and omized study was performed in which the impact of a cost attribute on the general public ’s preferences for a surgical treatment ( Mohs micrographic surgery [ MMS ] or st and ard excision [ SE ] ) to remove BCC was examined . This was done by comparing the outcomes of two DCEs , one with a cost attribute ( DCE_cost ) and one without ( DCE_nocost ) . Six attributes ( recurrence , re-excision , travel time , surgical time , waiting time for surgical results , costs ) and their levels were selected , based on results of a clinical trial , a cost-effectiveness study , a review and a focus group of patients who had recently received treatment for BCC . Outcomes of both DCEs were compared in terms of theoretical validity , relative importance of the attributes and the rank order of preferences . Results : A total of 615 respondents ( n = 303 for DCE_nocost ; n = 312 for DCE_cost ) were interviewed by telephone . This gave an overall response rate of 38%.Respondents in DCE_nocost preferred a surgical treatment with a lower probability of recurrence , lower surgery time , lower waiting time and no risk for a re-excision . Respondents in DCE_cost showed the same preferences , but also preferred a treatment with less travel time and lower costs . Overall , respondents in both DCEs showed the same preference for a surgical treatment : MMS  was preferred over SE . Conclusion : Results suggest that , in this population , the inclusion of a cost attribute in a DCE leads to the same preference regarding a surgical treatment to remove BCC as a DCE without a cost attribute . However , further research in different setting s is needed to confirm these findings Background Interventions in health care often not only have an effect on patients , but also on their informal caregivers . Caregiving can have a profound impact on the health and wellbeing of carers . Ignoring these spillovers in economic evaluations risks labelling interventions mistakenly as cost-effective , at the expense of informal caregivers . Objective This paper investigates willingness-to-accept ( WTA ) values for an hour of informal care , corrected for positive and negative impacts of informal care , to facilitate the inclusion of informal care hours on the cost side of economic evaluations without double-counting spillover effects . Methods A discrete choice experiment ( DCE ) was conducted among a representative sample of the adult population in the Netherl and s ( n = 552 ) in September 2011 . An experimental design minimizing the D-error was used to construct choice sets with two unlabelled alternatives with the attributes ‘ hours caregiving ’ , ‘ monetary compensation for caregiving ’ and seven impacts of caregiving . To operationalize the r and om utility model , we used a panel mixed multinomial logit ( MMNL ) parameter model . For calculation of WTA , we used both population -level parameters and individual-level parameters . Results The mean WTA for an additional hour of informal care , corrected for positive and negative impacts of informal care , was € 14.57 . The signs of the coefficients were all in the expected directions . Conclusions This study reports a preference-based monetary value for informal care , corrected for other impacts . This valuation facilitates the inclusion of informal care hours on the cost side in economic evaluations without double-counting any spillover effects included on the effects side At present there are no nephrology facilities in Greenl and . Greenl and ic patients with renal failure needing dialysis thus have to travel to Denmark to obtain treatment . For patients in haemodialysis this necessitates a permanent residence in Denmark . Our study was aim ed at examining Greenl and ers ’ preferences for  establishing nephrology facilities in Greenl and at Queen Ingrid ’s Hospital in Nuuk , and to estimate the associated change in welfare . Preferences were elicited using a discrete choice experiment ( DCE ) . A r and om sample of 500 individuals of the general population was sent a postal question naire in which they were asked to consider the trade-offs of establishing nephrology facilities in Greenl and as opposed to the current situation . This involved trading off the benefits of having such facilities in their home country against the costs of the intervention . Besides including a payment attribute described in terms of incremental tax payment , the DCE included two interventions attributes related to ( 1 ) the organisation of labour , and ( 2 ) the physical setting s of the patients . Respondents succeeded in answering the DCE despite cultural and linguistic disparity . We found that all the included attributes had a significant effect on respondents ’ choices , and that respondents ’ answers to the DCE were in keeping with their values as stated in the question naire . DCE data was analyzed using a r and om parameter logit model reparametrized in willingness-to-pay space . The results showed that establishing facilities in Greenl and were preferred to the current treatment in Denmark . The welfare estimate from the DCE , at DKK 18.74 million , exceeds the estimated annual costs of establishing treatment facilities for patients with chronic renal failure . Given the estimated confidence interval this result seems robust . Establishing facilities in Greenl and therefore would appear to be welfare-improving , deriving positive net benefits . Despite the relatively narrow policy focus , we believe that our findings provide some insight into individuals ’ preferences for de central ization of public services and on citizens ’ views of ‘ self-governance ’ that go beyond the case of Greenl and . More generally , this paper illustrates how DCE can be applied successfully to developing countries with culturally , demographically , and geographically distinct features Background and purpose An internet-based discrete choice experiment ( DCE ) was conducted to elicit preferences for a wide range of Dupuytren ’s contracture (DC)-related health states . An algorithm was subsequently developed to convert these preferences into health state utilities that can be used to assess DC ’s impact on quality of life and the value of its treatments . Methods Health state preferences for varying levels of DC h and severity were elicited via an internet survey from a sample of the UK adult population . Severity levels were defined using a combination of contractures ( 0 , 45 , or 90 degrees ) in 8 proximal interphalangeal and metacarpophalangeal joints of the index , middle , ring , and little fingers . Right-h and ed , left-h and ed , and ambidextrous respondents indicated which h and was preferable in each of the 10 r and omly-selected h and -pairings comparing different DC severity levels . For consistency across comparisons , anatomically precise digital h and drawings were used . To anchor preferences onto the traditional 0–1 utility scale used in health economic evaluations , unaffected h and s were assigned a utility of 1.0 whereas the utility for a maximally affected h and ( i.e. , all 8 joints set at 90 degrees of contracture ) was derived by asking respondents to indicate what combination of attributes and levels of the EQ-5D-5L profile most accurately reflects the impact of living with such h and . Conditional logistic models were used to estimate indirect utilities , then rescaled to the anchor points on the EQ-5D-5L . Results Estimated utilities based on the responses of 1,745 qualified respondents were 0.49 , 0.57 , and 0.63 for completely affected dominant h and s , non-dominant h and s , or ambidextrous h and s , respectively . Utility for a dominant h and with 90-degree contracture in t h e metacarpophalangeal joints of the ring and little fingers was estimated to be 0.89 . Separately , reducing the contracture of metacarpophalangeal joint for a little finger from 50 to 12 degrees would improve utility by 0.02 . Interpretation DC is associated with substantial utility decre- ments . The algorithms presented herein provide a robust and flexible framework to assess utility for varying degrees of DC severity Objective To elicit prescribers ' preferences for behavioural economics interventions design ed to reduce inappropriate antibiotic prescribing , and compare these to actual behaviour . Design Discrete choice experiment ( DCE ) . Setting 47 primary care centres in Boston and Los Angeles . Participants 234 primary care providers , with an average 20 years of practice . Main outcomes and measures Results of a behavioural economic intervention trial were compared to prescribers ' stated preferences for the same interventions relative to monetary and time rewards for improved prescribing outcomes . In the r and omised controlled trial ( RCT ) component , the 3 computerised prescription order entry-triggered interventions studied included : Suggested Alternatives ( SA ) , an alert that populated non-antibiotic treatment options if an inappropriate antibiotic was prescribed ; Accountable Justifications ( JA ) , which prompted the prescriber to enter a justification for an inappropriately prescribed antibiotic that would then be documented in the patient 's chart ; and Peer Comparison ( PC ) , an email periodically sent to each prescriber comparing his/her antibiotic prescribing rate with those who had the lowest rates of inappropriate antibiotic prescribing . A DCE study component was administered to determine whether prescribers felt  SA , JA , PC , pay-for-performance or additional clinic time  would most effectively reduce their inappropriate antibiotic prescribing . Willingness-to-pay ( WTP ) was calculated for each intervention . Results In the RCT , PC and JA were found to be the most effective interventions to reduce inappropriate antibiotic prescribing , whereas SA was not significantly different from controls . In the DCE however , regardless of treatment intervention received during the RCT , prescribers overwhelmingly preferred SA , followed by PC , then JA . WTP estimates indicated that each intervention would be significantly cheaper to implement than pay-for-performance incentives of $ 200/month . Conclusions Prescribing behaviour and stated preferences are not concordant , suggesting that relying on stated preferences alone to inform intervention design may eliminate effective interventions . Trial registration number NCT01454947 ; Results Health care policy background Findings from scientific studies form the basis for evidence -based health policy decisions . Scientific background Quality assessment s to evaluate the credibility of study results are an essential part of health technology assessment reports and systematic review s. Quality assessment tools ( QAT ) for assessing the study quality examine to what extent study results are systematic ally distorted by confounding or bias ( internal validity ) . The tools can be divided into checklists , scales and component ratings . Research questions What QAT are available to assess the quality of interventional studies or studies in the field of health economics , how do they differ from each other and what conclusions can be drawn from these results for quality assessment s ? Methods A systematic search of relevant data bases from 1988 onwards is done , supplemented by screening of the references , of the HTA reports of the German Agency for Health Technology Assessment ( DAHTA ) and an internet search . The selection of relevant literature , the data extraction and the quality assessment are carried out by two independent review ers . The substantive elements of the QAT are extracted using a modified criteria list consisting of items and domains specific to r and omized trials , observational studies , diagnostic studies , systematic review s and health economic studies . Based on the number of covered items and domains , more and less comprehensive QAT are distinguished . In order to exchange experiences regarding problems in the practical application of tools , a workshop is hosted . Results A total of eight systematic method ological review s is identified as well as 147 QAT : 15 for systematic review s , 80 for r and omized trials , 30 for observational studies , 17 for diagnostic studies and 22 for health economic studies . The tools vary considerably with regard to the content , the performance and quality of operationalisation . Some tools do not only include the items of internal validity but also the items of quality of reporting and external validity . No tool covers all elements or domains . Design -specific generic tools are presented , which cover most of the content criteria . Discussion The evaluation of QAT by using content criteria is difficult , because there is no scientific consensus on the necessary elements of internal validity , and not all of the generally accepted elements are based on empirical evidence . Comparing QAT with regard to contents neglects the operationalisation of the respective parameters , for which the quality and precision are important for transparency , replicability , the correct assessment and interrater reliability . QAT , which mix items on the quality of reporting and internal validity , should be avoided . Conclusions There are different , design -specific tools available which can be preferred for quality assessment , because of its wider coverage of substantive elements of internal validity . To minimise the subjectivity of the assessment , tools with a detailed and precise operationalisation of the individual elements should be applied . For health economic studies , tools should be developed and complemented with instructions , which define the appropriateness of the criteria . Further research is needed to identify study characteristics that influence the internal validity of studies BACKGROUND AND OBJECTIVE Previous work has suggested that people with poor health-related quality of life ( HR-QOL ) as a result of asthma are willing to pay the most for successful therapy . There is also evidence that preferences are an important influence on adherence to therapy . We report a patient preference study using a discrete-choice experiment ( DCE ) to elicit willingness to pay ( WTP ) of patients with asthma in Spain , the Netherl and s , and the UK . METHODS The DCE survey included different attributes of asthma therapy ( days with symptoms , days needing reliever medication , asthma attacks [ none , attack that does not require doctor/emergency room { ER } visit , attack that requires doctor/ER visit ] , risk of adverse effects , number of preventer inhalers , and monthly out-of-pocket costs ) . Participants indicated which attribute combinations they preferred . The question naire survey included the  mini Asthma Quality of Life Question naire ( mAQLQ ) .  The validity of the choice experiment has been supported by two pilot studies conducted in the UK . Preferences and WTP were estimated using a r and om effects probit model . Symptom days and asthma attack attributes were segmented by mAQLQ score . RESULTS Demographic and clinical data were compared between the three country sample s ( UK , n = 124 ; Spain , n = 86 ; the Netherl and s , n = 269 ) . All study attributes were independently significant predictors of choice . People were willing to pay € 35 per month to avoid a day with symptoms , and € 109 per month ( year 2005 values ) to avoid experiencing asthma attacks that required emergency visits to their doctor or hospital . People with the worst HR-QOL were willing to pay the least to avoid days with symptoms and asthma attacks that required visits to their doctor/ER . This was not an income-related effect . CONCLUSION Patients who reported higher HR-QOL  were willing to pay more to avoid days with symptoms and asthma attacks that required visits to their doctor/ER . Hypotheses were explored to explain this effect . It is possible that people with the least impairment of HR-QOL place the greatest value on avoiding the effects of asthma and so are most willing to alter their behavior . People with the worst HR-QOL may be exhibiting a response shift type of effect whereby their internal values are shifted down by the burden of their disease . These findings may help to illuminate why there are differences in asthma treatment adherence Background A discrete choice experiment ( DCE ) is a preference survey which asks participants to make a choice among product portfolios comparing the key product characteristics by performing several choice tasks . Analyzing DCE data needs to account for within-participant correlation because choices from the same participant are likely to be similar . In this study , we empirically compared some commonly-used statistical methods for analyzing DCE data while accounting for within-participant correlation based on a survey of patient preference for colorectal cancer ( CRC ) screening tests conducted in Hamilton , Ontario , Canada in 2002 . Methods A two-stage DCE design was used to investigate the impact of six attributes on participants ' preferences for CRC screening test  and willingness to undertake the test . We compared six models for clustered binary outcomes ( logistic and probit regressions using cluster-robust st and ard error ( SE ) , r and om-effects and generalized estimating equation approaches ) and three models for clustered nominal outcomes ( multinomial logistic and probit regressions with cluster-robust SE and r and om-effects multinomial logistic model ) . We also fitted a bivariate probit model with cluster-robust SE treating the choices from two stages as two correlated binary outcomes . The rank of relative importance between attributes and the estimates of βcoefficient within attributes were used to assess the model robustness . Results In total 468 participants with each completing 10 choices were analyzed . Similar results were reported for the rank of relative importance and βcoefficients across models for stage-one data on evaluating participants ' preferences for the test . The six attributes ranked from high to low as follows : cost , specificity , process , sensitivity , preparation and pain . However , the results differed across models for stage-two data on evaluating participants ' willingness to undertake the tests . Little within-patient correlation ( ICC ≈ 0 ) was found in stage-one data , but substantial within-patient correlation existed ( ICC = 0.659 ) in stage-two data . Conclusions When small clustering effect presented in DCE data , results remained robust across statistical models . However , results varied when larger clustering effect presented . Therefore , it is important to assess the robustness of the estimates via sensitivity analysis using different models for analyzing clustered data from DCE studies Abstract Purpose Real‐world evidence ( RWE ) includes data from retrospective or prospect i ve observational studies and observational registries and provides insights beyond those addressed by r and omized controlled trials . RWE studies aim to improve health care decision making . Methods The International Society for Pharmacoeconomics and Outcomes Research ( ISPOR ) and the International Society for Pharmacoepidemiology ( ISPE ) created a task force to make recommendations regarding good procedural practice s that would enhance decision makers ' confidence in evidence derived from RWD studies . Peer review by ISPOR/ISPE members and task force participants provided a consensus‐building iterative process for the topics and framing of recommendations . Results The ISPOR/ISPE Task Force recommendations cover seven topics such as study registration , replicability , and stakeholder involvement in RWE studies . These recommendations , in concert with earlier recommendations about study methodology , provide a trustworthy foundation for the exp and ed use of RWE in health care decision making . Conclusion The focus of these recommendations is good procedural practice s for studies that test a specific hypothesis in a specific population . We recognize that some of the recommendations in this report may not be widely adopted without appropriate incentives from decision makers , journal editors , and other key stakeholders Background How women experience childbirth is acknowledged as critical to the postnatal wellbeing of mother and baby . However there is a knowledge deficit in identifying the important elements of these experiences in order to enhance care . This study elicits women ’s preferences for the most important elements of their childbirth experiences . Methods A mixed methods design was used . An initial qualitative phase ( reported previously ) was followed by a second quantitative one using a discrete choice experiment ( DCE ) , which is reported on here . Participants who had experienced labour , were over 18 and had a healthy baby were recruited from four r and omly selected and one pilot hospital in the Republic of Irel and . Data were collected by means of a DCE survey instrument . Questions were piloted , refined , and then arranged in eight pair-wise scenarios . Women identified their preferences by choosing one scenario over another . Nine hundred and five women were sent the DCE three months after childbirth , with a response rate of 59.3 % ( N = 531 ) . Results Women clearly identified priorities for their childbirth experiences as : the availability of pain relief , partnership with the midwife , and individualised care being the most important attributes . In the context of other choices , women rated decision-making , presence of a consultant , and interventions as less important elements . Comments from open questions provided context ual information about their choices . Conclusions Most women did not want to be typified as wanting the dichotomy of ‘ all natural ’ or ‘ all technology ’ births but wanted ‘ the best of both worlds ’ . The results suggest that availability of pain relief was the most important element of women ’s childbirth experiences , and superseded all other elements including partnership with the midwife which was the second most important attribute . The preferences identified might reflect the busy medicalised hospital environments , in which the vast majority of women had given birth , and may differ in setting s such as midwifery led care or home births 626 pages , 2012 , Academic Press , 2012 , Arthur J. Atkinson ( Jr. ) , Shiew-Mei Huang , Principles of Clinical Pharmacology , 0123854717 , 9780123854711 , Principles of Clinical Pharmacology is a successful survey covering the pharmacologic principles underlying the individualization of patient therapy and contemporary drug development . This essential reference continues to focus on the basics of clinical pharmacology for the development , evaluation , and clinical use of pharmaceutical products while also addressing the most recent advances in the field . Written by leading experts in academia , industry , clinical and regulatory setting s , the third edition has been thoroughly up date d to provide readers with an ideal reference covering the wide range of important topics impacting clinical pharmacology as the discipline plays an increasingly significant role in drug development and regulatory science . The Third Edition has been endorsed by the American Society for Clinical Pharmacology and Therapeutics * Includes new chapters on imaging and the pharmacogenetic basis of adverse drug reactions . * Offers an exp and ed regulatory section that addresses US and international issues and guidelines . * Provides extended coverage of earlier chapters on transporters , pharmacogenetics and biomarkers and also illustrates the impact of gender on drug response . * Presents a broadened discussion of clinical trials from Phase 1 to incorporate Phases II and III . file download OBJECTIVES To examine GPs ' preferences for organisational characteristics in general practice with focus on aspects that can potentially mitigate problems with GP shortages . METHODS A simple r and om sample of 1823 GPs ( corresponding to half of all GPs in Denmark ) was drawn at the beginning of 2010 , and a response rate of 68 % was obtained . A discrete choice experiment ( DCE ) is applied , and attributes included are :  practice type ( solo/shared ) , number of GPs in general practice , collaboration with other practice s ( yes/no ) , change in weekly working hours ( administrative versus patient related ) and change in yearly surplus . Multinomial logit analyses ( with and without interaction variables ) are used , and marginal rates of substitution are calculated . RESULTS GPs working in solo practice s have different preferences for the organisational attributes compared to GPs in shared practice s. The compensation needed for GPs to re-organise from solo to shared practice is associated with the size of the practice . GP characteristics such as age , working hours and surplus affect their willingness to undergo organisational changes . CONCLUSIONS Our results are of relevance to decision makers in design ing policies aim ed at influencing GPs ' organisation in order to overcome problems related to shortages BACKGROUND Evidence -based public health decision-making depends on high quality and transparent accounts of what interventions are effective , for whom , how and at what cost . Improving the quality of reporting of r and omized and non-r and omized study design s through the CONSORT and TREND statements has had a marked impact on the quality of study design s. However , public health users of systematic review s have been concerned with the paucity of synthesized information on context , development and rationale , implementation processes and sustainability factors . METHODS This paper examines the existing reporting frameworks for research against information sought by users of systematic review s of public health interventions and suggests additional items that should be considered in future recommendations on the reporting of public health interventions . RESULTS Intervention model , theoretical and ethical considerations , study design choice , integrity of intervention/process evaluation , context , differential effects and inequalities and sustainability are often overlooked in reports of public health interventions . CONCLUSION Population health policy makers need synthesized , detailed and high quality a priori accounts of effective interventions in order to make better progress in tackling population morbidities and inequalities . Adding simple criteria to reporting st and ards will significantly improve the quality and usefulness of published evidence and increase its impact on public health program planning There is a growing recognition that insufficient attention has been paid to the selection of the outcomes to measure in clinical trials and clinical audit . Outcomes need to be relevant to patients , clinicians , purchasers and policy-makers if the findings of research are to influence practice and future research . In addition , st and ardization of outcomes is needed to combine data from different studies to allow evidence synthesis and to compare data sets . Inconsistent choice of outcome measures means that many meta-analyses are unable to include data from all the relevant studies . For example , the five most accessed Cochrane review s in 2009 , together with the top cited review in that year , all described inconsistencies in the outcomes reported in eligible trials . A call for the st and ardization of outcomes is a regular conclusion of systematic review s. Furthermore , outcome reporting bias , defined as the bias arising from selecting outcomes for publication based on the results , affects many r and omized trials and ‘ is an under-recognized problem that affects the conclusions in a substantial proportion of Cochrane review s ’ . That bias is likely to affect systematic review s more widely as well as affecting individual studies when considered on their own . Similar problems occur with clinical audit , highlighting the importance of establishing national audits that use and report the same outcomes for all participants . All these issues could be addressed with the development and application of agreed st and ardized sets of outcomes that have been termed ‘ core outcome sets ’ . These should be measured and reported , as a minimum , in all relevant clinical trials and national clinical audits for a specific condition . Adopting a core outcome set does not imply that a particular study , review or audit should be restricted to only those outcomes . Rather , the expectation is that , as a minimum , core outcomes will always be collected and reported to allow the results of trials to be compared , contrasted and combined as appropriate . The adoption of core outcomes would have implication s across all areas of research in health and health care , reduce heterogeneity between trials , and lead to research that is more likely to have measured relevant outcomes . Importantly , they would enhance the value of evidence synthesis by reducing the risk of outcome reporting bias and ensuring that all trials contribute usable information . In addition , they will increase the efficiency and value of research . An important rationale for core outcome sets is that outcomes currently reported for trials do not consistently reflect endpoints that are meaningful for patients . Examples exist where trials failed to include all outcomes important to patients and where involvement of patients has identified an outcome that might not have been considered by practitioners on their own . Despite increasing recognition of the importance of incorporating patients ’ opinions , their involvement has been limited . Recent regulatory guidance in the USA requires documented evidence of patient input during the development of instruments to measure  patient reported outcomes ( PROs ) . However , measurement of PROs in clinical trials is hampered by the multiplicity and heterogeneity of tools currently available . Many generic , disease and domain-specific instruments have been developed and vali date d , each containing multiple scales and items . As a result , synthesis of PRO data from trials is difficult and review s aim ing to summarize treatment effect according to PROs may fail . There is synergy between the development of core outcome sets for trials and work to select up to seven outcomes that are important to patients for inclusion in Summary of Findings tables in systematic review s. Developed by the GRADE group ( http://www . grade workinggroup.org ) , Cochrane review s have featured such tables since 2008 , and they play a key role in presenting research in guidelines , such as those produced by the World Health Organization ( WHO ) . The development of core outcome sets needs to be accelerated and undertaken in ways that maximize efficiency . The COMET ( Core Outcome Measures in Effectiveness Trials , http://www.comet-initiative.org ) Initiative in the UK brings together research ers interested in the development and application of core outcome sets . These include key participants in a collaboration of research ers in rheumatology who have done the most notable work to date in this area . The COMET Initiative was launched in January 2010 , with a second meeting in July 2011 . Attendees included trialists , systematic review ers , patients , clinicians , journal editors , research funders , policy-makers , people responsible for trials registries and regulators . Data on individual studies , both published and ongoing , are being included in a free , publically available internet-based re source . This will be up date d periodically , to minimize the risk of duplication . Seventy-eight published or ongoing studies have already been entered into the repository . In addition , published review s of outcomes used in clinical trials or studies examining patients ’ views , will be entered Health systems worldwide are grappling with the need to control costs to maintain system viability . With the combination of worsening economic conditions , an aging population and reductions in tax revenues , the pressures to make structural changes are expected to continue growing . Common cost control mechanisms , e.g. curtailment of patient access and treatment prioritization , are likely to be adversely viewed by citizens . It seems therefore wise to include them in the decision making processes that lead up to policy changes . In the context of a multilevel iterative mixed- method design a quantitative survey representative of the German population ( N = 2031 ) was conducted to probe the acceptance of priority setting in medicine and to explore the practicability of direct public involvement . Here we focus on preferences for patients ' characteristics ( medical aspects , lifestyle and socio-economic status ) as possible criteria for prioritizing medical services . A question naire with closed response options was fielded to gain insight into attitudes toward broad prioritization criteria of patient groups . Furthermore , a discrete choice experiment was used as a rigorous approach to investigate citizens ' preferences toward specific criteria level in context of other criteria . Both the question naire and the discrete choice experiment were performed with the same sample . The citizens ' own health and social situation are included as explanatory variables . Data were evaluated using corresponding analysis , contingency analysis , logistic regression and a multinomial exploded logit model . The results show that some medical criteria are highly accepted for prioritizing patients whereas socio-economic criteria are rejected Background There is increasing pressure to address the social determinants of health ( SDoH ) and health inequities through the implementation of culturally acceptable interventions particularly in Sub-Saharan Africa ( SSA ) where health outcomes are generally poor . Available evaluation research on cash transfers ( CTs ) suggests that the programs may influence the wider determinants of health in SSA ; yet , there has been no attempt to synthesize the evidence regarding their contribution to tackling the SDoH and health inequalities . To date , nearly all the review s on CTs ' impact on health have predominantly featured evidence from Latin America with limited transferability to the social , cultural , and political environments in SSA . Therefore , the aim of this study is to undertake a systematic review to assess the role of CTs in tackling the wider determinants of health and health inequalities in SSA . Methods / design A systematic review of published and unpublished literature on CTs ’ impact on health and health determinants covering the period 2000–2016 will be undertaken . Studies will be considered for inclusion if they present quantitative or qualitative data , including all relevant study design s. The SDoH conceptual framework will be used to guide the data extraction process . EPPI Review er software will be used for data management and analysis . Studies included in the review will be analyzed by narrative synthesis and /or meta- analysis as appropriate for the nature of the data retrieved . Discussion This review will provide empirical evidence on the impact of CTs on SDoH to inform CT policy , implementation , and research in SSA . The protocol follows the Preferred Reporting Items for Systematic Review and Meta- Analysis Protocol s ( PRISMA -P ) . Systematic review registration This protocol has been registered with the PROSPERO international prospect i ve register of systematic review s , reference CRD42015025015 Background Health systems worldwide are facing shortages in health professional workforce . Several studies have demonstrated the direct correlation between the availability of health workers , coverage of health services , and population health outcomes . To address this shortage , online eLearning is increasingly being adopted in health professionals ’ education . To inform policy – making , in online eLearning , we need to determine its effectiveness . Methods We performed a systematic review of the effectiveness of online eLearning through a comprehensive search of the major data bases for r and omised controlled trials that compared online eLearning to traditional learning or alternative learning methods . The search period was from January 2000 to August 2013 . We included articles which primarily focused on students ' knowledge , skills , satisfaction and attitudes toward eLearning and cost-effectiveness and adverse effects as secondary outcomes . Two review ers independently extracted data from the included studies . Due to significant heterogeneity among the included studies , we presented our results as a narrative synthesis . Findings Fifty – nine studies , including 6750 students enrolled in medicine , dentistry , nursing , physical therapy and pharmacy studies , met the inclusion criteria . Twelve of the 50 studies testing knowledge gains found significantly higher gains in the online eLearning intervention groups compared to traditional learning , whereas 27 did not detect significant differences or found mixed results . Eleven studies did not test for differences . Six studies detected significantly higher skill gains in the online eLearning intervention groups , whilst 3 other studies testing skill gains did not detect differences between groups and 1 study showed mixed results . Twelve studies tested students ' attitudes , of which 8 studies showed no differences in attitudes or preferences for online eLearning . Students ' satisfaction was measured in 29 studies , 4 studies showed higher satisfaction for online eLearning and 20 studies showed no difference in satisfaction between online eLearning and traditional learning . Risk of bias was high for several of the included studies . Conclusion The current evidence base suggests that online eLearning is equivalent , possibly superior to traditional learning . These findings present a potential incentive for policy makers to cautiously encourage its adoption , while respecting the heterogeneity among the studies The Bulletin ’s editorial team has decided to encourage systematic review s. This is an important decision and is to be welcomed . However it is possible that it will not be received positively by all . Some may feel that systematic review s are not suitable for answering wider public health questions , and that the new section will simply result in the publication of systematic review s addressing narrowly focused , clinical questions with a focus on r and omized controlled trials alone.1 There is no reason why this should be so , and there are far too many examples of systematic review s of non- clinical interventions ( including government policies ) , which include non-r and omized studies , to list.2 Systematic review s of qualitative research are also becoming more common.3 Nonetheless misconceptions about the scope and flexibility of systematic review s still surface occasionally and it never fails to surprise me when I stumble across one of these hoary old chestnuts . If it really were true that systematic review s were only for simple , individual-level interventions , systematic review ers working in public health would be very concerned . After all , public health problems require us to draw on complex sets of qualitative as well as quantitative evidence ; and some policy interventions have never been subjected to r and omized controlled trials ( RCTs ) but have been evaluated using other approaches ; everything from controlled and uncontrolled before- and -after studies , to time series analyses , to qualitative methods . In such cases , systematic review s that focused on RCTs alone would have little to say and we would end up producing many “ empty review s ” , which contain no studies at all . These would be undoubtedly quicker to do and quicker to read than the typical systematic review , but would be of limited use for making policy . However this is not the case . In public health we already have a wealth of review s that prioritize RCTs where they are available , but which draw upon a range of other evidence where they are appropriate to answering the review question .2 Take , as an example , transport policies , an important social determinant of health.4 Public health decision-makers have been interested in the effects on health of building new roads for decades , but there has never been a r and omized controlled trial , for obvious reasons . Yet it would make no sense to cl aim that there is no evidence to be review ed ; rather , there have been many controlled and uncontrolled studies that have examined the effects of new roads on respiratory symptoms , injuries , community severance , disturbance and a variety of other outcomes of public health importance . These studies have in fact been systematic ally review ed.5 Many other examples of review s of complex interventions that impact on public health could be given , which appear on the Cochrane Data base and elsewhere,6,7 and such review s are the main focus of the recently-established Cochrane Public Health Review Group . It is also worth noting that both the Cochrane and Campbell Collaboration include increasing numbers of review s that are relevant to low- and middle- income countries,8 though there is a particular need for more systematic review s that consider the effects on equity of the interventions that they include.9 Currently systematic review s have a “ utilitarian bias ” – they tend to be concerned more with the effects on population s and average effects than with distributional effects and impacts in disadvantaged subgroups . It is to be hoped that systematic review s su bmi tted to the Bulletin will routinely consider the effects of interventions on health inequities . The Cochrane Health Equity Field ( http://equity.cochrane.org/en/index.html ) was set up explicitly to further this agenda , to encourage systematic review authors to explicitly assess the effects of interventions not only on the whole population , but on the disadvantaged . So where does this leave non- systematic review s ? Should every review be a systematic review ? This is a difficult question to answer in a short editorial . My own view is that not all review s need to be systematic review s ; there is still a place for review papers that provide a broad overview , and that discuss a range of evidence and make a contribution to wider debates about what might work in particular setting s. However , while such discussion s help place evidence in context and suggest how it may be used , they should not be confused with the evidence -based conclusions of a transparent , scientific review , which systematic ally attempts to find all the relevant evidence , appraises its strengths and limitations in a transparent fashion , and draws that evidence together in such a way that the more robust studies are given greater weight . Finally , the challenges are many . Evidence on interventions to improve public health is in short supply , particularly evidence on social determinants . Systematic review ers therefore face a real challenge in making best use of the sometimes poor , often sparse and usually heterogeneous evidence available to them . It is easy to set narrow inclusion criteria for a review and then sift through the evidence before concluding that there is n’t enough – and what there is , is n’t very good anyway . Such “ evidential nihilism ” is probably not helpful to decision-makers , and public health systematic review ers need to continue to develop new methods and better frameworks within which different types of research evidence can be integrated to inform decision-making . Publishing systematic review s in the Bulletin should give an added impetus to this ongoing work . Support for prospect i ve registration of protocol s for systematic review s has been gathering momentum . The PRISMA statement , a guideline for reporting systematic review s and meta-analyses of studies that evaluate health-care interventions , advocates registration . Well-conducted systematic review s are accepted as the best- quality evidence to inform policy and practice , and the dramatic upward trend in the number of systematic review s published annually ( fi gure ) is set to continue . However , there is currently no single facility for identifying this type of research in advance of the appearance of the results of the review . There is concern about and evidence of publication and selective outcome -reporting biases associated with systematic review s. An open registry of review s captured at the protocol stage would facilitate good practice in systematic review s by providing transparency of the review process and outcomes . Discrepancies between the methods of the published review and those planned in the registered protocol could be more readily identifi ed . Registration might also encourage full publication of the review ’s fi ndings and transparency in changes to methods that could bias fi ndings . In both the prevention and revelation of potential bias , registration should improve quality and increase confi dence that policy or practice informed by the fi ndings of systematic review s are indeed drawing on best- quality evidence . A registry of protocol s of systematic review s could assist those planning new review s and updating existing ones . Easy access to information about ongoing review s should help to optimise the use of fi nite re sources by enabling funding and commissioning agencies to avoid unnecessary duplication and encourage collaboration . A comprehensive registry could also create opportunities for method ological and other research , both within and across disciplines . Existing access to systematic - review protocol s is limited to the outputs of individual organisations , such as the Cochrane and Campbell Collaborations and the Joanna Briggs Institute . The National Public Health Service for Wales is piloting an All Wales Systematic Review s Register , but , up to now , there has been no central ised comprehensive registry of systematic - review protocol s. We are developing an international facility to register the details of ongoing systematic review s in health and social care . Our registry is being established with the existing platform and infrastructure that supports the Data base of Abstract s of Review s of Eff ects ( DARE ) , the NHS Economic Evaluations Data base ( NHS EED ) and the Health Technology Assessment ( HTA ) data base produced by the Centre for Review s and Dissemination . The initial scope of the registry will be limited to systematic review s of the eff ectiveness of health interventions . However , the longterm aim is for the registry to include details of all ongoing systematic review s with a health-related outcome in the broadest sense . Ultimately , inclusion will encompass systematic review s of health-care interventions , and review s of the social determinants of health , of service delivery , and of risk factors and genetic associations . Our web-based registry will off er free public access , be electronically search able , and open to all prospect i ve registrants . Registration will require the provision of a minimum data set , the completeness of which will be checked automatically before registration . After acceptance , the registry ’s entry and protocol for the review , if available , will be loaded on the data base as a permanent entry and a unique identifi cation number issued . An audit trail for any amendments to the information will be available within the record . Links to result ing publications will be added . These provisions ensure that the registry will match the relevant criteria required of clinical trials registries Numerous authoritative reports have identified environmental and policy interventions as the most promising strategies for creating population -wide improvements in diet , physical activity , and obesity . Yet many method ologic challenges to conducting environmental and policy research must be overcome to enable this area of study to advance . A meeting titled " Study Design s and Analytic Strategies for Environmental and Policy Research on Obesity , Physical Activity , and Diet " was held April 8 , 2008 . Participants from diverse background s identified priority gaps in knowledge and generated recommendations for promising methods to enhance environmental and policy research related to obesity . Final recommendations were based on a postmeeting participant survey . Existing methods were identified that could be applied to advance the field , including prospect i ve studies , evaluations of natural experiments , and economic studies . Training for investigators in the use of appropriate statistical methods for complex design s and interdisciplinary collaboration were recommended . Method ologic research priorities included the development of measures of policy , health impact assessment s , and the investigation of policy adoption and implementation . The results of this conference can be used to improve the quality and quantity of environmental and policy research as well as the translation to action to control obesity The major strength of a r and omised controlled trial ( RCT ) is the degree to which it can establish a causal relationship between an experimental treatment and the outcome ( i.e. internal validity ) , as r and omisation should ensure that potential confounders are equally distributed over the treatment and control arms . Internal validity in RCTs can be threatened , however , by multiple sources of bias . For example , poor r and omisation procedures ( e.g. failure to conceal allocations until treatments have been assigned ) can lead to selection bias because more high-risk individuals are selected to receive the experimental treatment . There is a range of potential sources of bias in RCTs , and several well-known tools for assessing the risk of bias provide useful overviews of these sources and strategies for reducing them ( e.g. Guyatt et al. , 2011 ; Higgins , Altman , & Sterne , 2011 ) . These tools are also influential : trials scoring high on risk-of-bias assessment s should have a smaller chance on publication and – if published – to be included in ‘ best evidence ’ systematic review s ( Johnson , Low , & MacDonald , 2015 ) , and thus for their interventions to influence policy and practice . Systematic review s suggest that many health behaviour change ( HBC ) trials suffer from a moderate to high risk of bias ( e.g. Oberjé , de Kinderen , Evers , van Woerkum , & de Bruin , 2013 ; Poobalan , Aucott , Precious , Crombie , & Smith , 2009 ) ; more so than , for example , drug trials ( Crocetti , Amin , & Scherer , 2010 ) . Moreover , risk-of-bias scores have been found to explain heterogeneity in effect sizes , especially in trials with subjective outcome measures ( Savovic et al. , 2012 ; Wood et al. , 2008 ) . Since replication studies of HBC intervention evaluations are uncommon , invalid inferences due to bias may not be easily discovered and rectified . Despite these concerns , there has been little attention in the behaviour change intervention literature to the sources and consequences of bias in trials , and to strategies that may be effective in reducing the risk of bias . This paucity of research on risk of bias in HBC trial is in turn reflected in widely used instruments for assessing the risk of bias , such as the Cochrane risk-of-bias tool ( Higgins et al. , 2011 ) , which seems to be mostly based on evidence from non-behavioural trials . The objective of this special issue is to reflect on the evidence , practice s and challenges in relation to reducing the risk of bias in HBC trials . We hope that this special issue will both impact scientific practice ( i.e. enhancing the quality of HBC trial design , reporting and synthesis ) and have an agenda- setting effect ( i.e. inspire people to do empirical research into what sources of bias actually do affect HBC trials , what strategies are effective for mitigating these , and thus what criteria should be used for grading the quality of the evidence of HBC trials ) Purpose : To estimate consumer utilities associated with major attributes of retail clinics ( RCs ) . Data sources : A discrete choice experiment ( DCE ) with 383 adult residents of the metropolitan statistical areas in Georgia conducted via R and om Digit Dial survey of households . The DCE had two levels each of four attributes : price ( $ 59 ; $ 75 ) , appointment wait time ( same day ; 1 day or more ) , care setting ‐provider combination  ( nurse practitioner  [NP]‐RC ; physician‐private office ) , and acute illness ( urinary tract infection ; influenza ) , result ing in 16 choice scenarios . The respondents indicated whether they would seek care under each scenario . Conclusions : Cost savings and convenience offered by RCs are attractive to urban patients , and given sufficient cost savings they are likely to seek care there . All else equal , one would require cost savings of at least $ 30.21 to seek care from an NP at RC rather than a physician at private office , and $ 83.20 to wait one day or more . Implication s for practice : Appointment wait time is a major determinant of careseeking decisions for minor illnesses . The size of the consumer utility associated with the convenience feature of RCs indicates that there is likely to be further growth and employment opportunities for NPs in these clinics Summary In Spain , various treatments are available to prevent osteoporotic fractures . A discrete choice experiment ( DCE ) was used to investigate the importance of different treatment aspects and its influence on patients ’ preferences . All attributes included as type and place of drug administration as well as costs showed to be significant predictors of choice . Spanish osteoporosis patients have well-defined preferences and accept trade-offs among attributes . Introduction This study was design ed to identify patient preferences for different aspects of osteoporosis treatments in Spain . Methods Main attributes of severe osteoporosis treatments were determined by literature review and consultations with nurses . The discrete choice experiment included three attributes : type of drug administration , place of administration , plus a cost attribute in order to estimate willingness to pay for improvements in attribute levels . A pilot study with 50 patients was performed to identify the areas of misunderst and ing . One hundred sixty-six patients with a diagnosis of osteoporosis and severe osteoporosis were presented with pairs of hypothetical treatment profiles with different type of administration levels , places of administration and costs . Questions to collect socio-demographic and disease-related treatment data were also included . Data were analysed using a r and om effects probit model . Results All attributes had the expected polarity and were significant predictors of choice . Patients were willing to pay 183 € /month to have a subcutaneous injection once per day rather than an intravenous injection once per year . Patients with osteoporosis were willing to pay 121 € /month to have medical support when administering the drug treatment at home rather than being admitted several hours to a hospital for drug administration . ConclusionS panish osteoporosis patients have well-defined preferences among treatment attributes and are willing to accept trade-offs among attributes . Participants indicated that they are willing to accept self medication with medical support rather than being hospitalised for several hours . The perspective of the patients should be taken into account when making treatment decisions Background Ten years on from the National Institute of Health and Clinical Excellence ’ technology appraisal guideline on haemodialysis in 2002 ; the clinical community is yet to rise to the challenge of providing home haemodialysis ( HHD ) to 10 - 15 % of the dialysis cohort . The renal registry report , suggests underutilization of a treatment type that has had a lot of research interest and several publications worldwide on its apparent benefit for both physical and mental health of patients . An underst and ing of the drivers to introducing and sustaining the modality , from organizational , economic , clinical and patient perspectives is fundamental to realizing the full benefits of the therapy with the potential to provide evidence base for effective care models . Through the BASIC-HHD study , we seek to underst and the clinical , patient and carer related psychosocial , economic and organisational determinants of successful uptake and maintenance of home haemodialysis and thereby , engage all major stakeholders in the process . Design and methods We have adopted an integrated mixed methodology ( convergent , parallel design ) for this study . The study arms include a. patient ; b. organization ; c. carer and d. economic evaluation . The three patient study cohorts ( n = 500 ) include pre-dialysis patients ( 200 ) , hospital haemodialysis ( 200 ) and home haemodialysis patients ( 100 ) from geographically distinct NHS sites , across the country and with variable prevalence of home haemodialysis . The pre-dialysis patients will also be prospect ively followed up for a period of 12 months from study entry to underst and their journey to renal replacement therapy and subsequently , before and after studies will be carried out for a select few who do commence dialysis in the study period . The process will entail quantitative methods and ethnographic interviews of all groups in the study . Data collection will involve clinical and biomarkers , psychosocial quantitative assessment s and neuropsychometric tests in patients . Organizational attitudes and dialysis unit practice s will be studied together with perceptions of healthcare providers on provision of home HD . Economic evaluation of home and hospital haemodialysis practice s will also be undertaken and we will apply scenario ( " what … if " ) analysis using system dynamics modeling to investigate the impact of different policy choices and financial models on dialysis technology adoption , care pathways and costs . Less attention is often given to the patient ’s carers who provide informal support , often of a complex nature to patients afflicted by chronic ailments such as end stage kidney disease . Engaging the carers is fundamental to realizing the full benefits of a complex , home-based intervention and a qualitative study of the carers will be undertaken to elicit their fears , concerns and perception of home HD before and after patient ’s commencement of the treatment . The data sets will be analysed independently and the findings will be mixed at the stage of interpretation to form a coherent message that will be informing practice in the future . Discussion The BASIC-HHD study is design ed to assemble pivotal information on dialysis modality choice and uptake , investigating users , care-givers and care delivery processes and study their variation in a multi-layered analytical approach within a single health care system . The study results would define modality specific service and patient pathway re design . Study Registration This study has been review ed and approved by the Greater Manchester West Health Research Authority National Research Ethics Service ( NRES ) The study is on the NIHR ( CLRN ) portfolio PHP289 A SyStemAtic Review of tHe imPAct of imPRoved HouSing inteRventionS on HeAltH in low And middle income tRoPicAl Setting S Butt T1 , Von Seidlein L2 1University College London , London , UK , 2Mahidol Oxford Tropical Medicine Research Unit , Bangkok , Thail and Objectives : Housing has a major impact on human health and wellbeing in the developing world directly ( e.g. through household accidents ) and indirectly ( e.g. through mediating contact between occupants and disease vectors ) . The objective of this review was to investigate the impact of improved housing on health in tropical zones of low and middle income countries . MethOds : A systematic review of major health and architecture data bases was conducted in order to identify records reporting the impact of housing features on the health of people living in tropical regions . Information was extracted and reported using a st and ardised form . Results were classified by study characteristics and qualitative trends explored . Results : We identified 120 studies that met the inclusion criteria . Studies covered vector-borne , gastrointestinal and respiratory diseases and household injuries . 76 were observational , 27 were trials ( including 11 r and omised controlled trials ) , 9 were models and 7 were studies considering economic aspects of  housing interventions . Of the economic studies identified , 3 were cost benefit analysis , 3 were cost per disability-adjusted life year ( DALY ) , while 1 measured burden of disease in DALYs . Outcomes were classified as economic ( 7 ) such as DALYs , direct health ( 57 ) such as incidence of diarrhoea , indirect health such as question naires ( 16 ) or surrogate ( 39 ) such as mosquito counts in a house . cOnclusiOns : There have been a considerable number of studies investigating the impact of housing features on health in tropical regions . Most focused on the impact of one or more housing feature on one or more health outcome . A smaller number of studies looked at whole house interventions and there have been few economic evaluations of improved housing interventions . A holistic approach to assessing health in the context of housing and consideration of issues of economics and implementation would be valuable topics for future research OBJECTIVES Little is known about doctors ' preferences regarding public report card design .  Taiwan just announced the first diabetes report card on April 2008 . The aim of this study was to investigate the Diabetes Mellitus ( DM ) providers ' preferences towards four report card attributes : up date frequency , risk adjustment , content information and display format . METHODS A discrete choice question naire  was mailed to hospital and primary care doctors in the northern part of Taiwan , with 221 study targets . The response rate was 29 % . RESULTS Using r and om effect logistic regression , doctors ' preference attribute rankings were risk adjustment for patients ( 44.7 % ) , content information ( 25.2 % ) , display format ( 18.3 % ) and up date frequency ( 11.8 % ) . One-year up date frequency , risk adjustment , detailed scores of technical quality and interpersonal quality and bar chart display were the most important items noted in our survey . CONCLUSIONS This is the first study to investigate provider 's preferences for a diabetes report card . It enables the policy maker to clearly see the implication of trade-offs between different choices when design ing a report card that doctors will like . Our findings suggest that doctors do not favour the ' less is more ' principle , or the higher frequency of up date s that patients may prefer . Rather , our findings suggest that risk adjustment and more information content are the most important factors for doctors . Future studies should use discrete choice experiment on different aspects of report card design , such as vulnerable patients or health care administrations Results for health-related quality of life ( HRQoL ) from clinical trials are increasingly used for clinical decision making as well as comparative eff ectiveness , health policy , and reimbursement decisions . Research suggests that HRQoL information can be used to establish treatment preferences because patients value HRQoL data and can interpret HRQoL fi ndings accurately . Trials that incorporate HRQoL as an outcome should therefore be design ed , analysed , and reported well . We did a systematic review of the literature and identifi ed 18 publications with guidelines or st and ards for reporting of HRQoL in r and omised controlled trials , which draw attention to the need for good quality in both trial design and reporting . With regard to trial design , examples of key quality criteria include : the need to use reliable and valid HRQoL measures that are appropriate for the population of interest and that include core outcomes agreed by clinicians , research ers , and patients ; timing of HRQoL assessment that is relevant to clinical interpretation of results ; minimisation of missing data ( since data are often not missing r and omly , but instead could be linked to other clinical outcomes of interest , with those most unwell not providing data ) ; and use of prespecifi ed statistical analyses to avoid multiple statistical testing and selective reporting of results . Given these and other requirements for quality st and ards in clinical trial design , many authors have recommended st and ards for HRQoL reporting so that readers of trial reports can ascertain whether quality st and ards have been reached . Such st and ard criteria have included , for example , the provision of a clear rationale for the domains of HRQoL assessment ( eg , specifi c symptoms such as pain , or functions such as activity levels ) and the corresponding choice of HRQoL instrument , with cited evidence of the instrument ’s validity and a statement about the timing of HRQoL assessment s used in the trial . Trials should report baseline compliance and the extent of subsequent missing data , since reports that omit details about the amount of missing data , or report substantial missing data , should be interpreted with caution . Type 1 statistical errors , result ing from multiple statistical testing , can be addressed by the requirement that trial protocol s prespecify the principal HRQoL postulated outcomes , and their respective timepoints for analysis and reporting in the fi nal trial publication . Finally , reporting of HRQoL data in a comprehensible , clinical ly applicable format , and in the context of other trial outcomes might better promote the use of HRQoL data in practice . Despite these existing recommendations , a systematic review of 794 r and omised trials undertaken between 2002 and 2008 that reported HRQoL outcomes across a range of medical conditions showed that only 56 % of trials provided a rationale for the selected outcome measure , 50 % provided an HRQoL hypothesis , 28 % provided information about missing data , and 36 % did not discuss the HRQoL fi ndings in the context of the other trial outcomes . The review noted that when HRQoL data 8 Ezzati M , Kammen DM . Indoor air pollution from biomass combustion and acute respiratory infections in Kenya : an exposure-response study . Lancet 2001 ; 358 : 619–24 . 9 Naeher LP , Smith KR , Leaderer BP , Mage D , Grajeda R. Indoor and outdoor PM2.5 and CO in high and low-density Guatemalan villages . J Expo Anal Environ Epidemiol 2000 ; 10 : 544–51 . 10 Barraza-Villarreal A , Sunyer J , Hern and ez-Cadena L , et al. Air pollution , airway infl ammation , and lung function in a cohort study of Mexico City schoolchildren . Environ Health Perspect 2008 ; 116 : 832–38 . 11 Moshammer H , Hoek G , Luttmann-Gibson H , et al.  Parental smoking and lung function in children : an international study . Am J Respir Crit Care Med 2006 ; 173 : 1255–63 . 12 Miller RL , Daswani M , Lendor C. Prenatal exposure to air pollution and respiratory outcomes in children . In : Jeorgenson NA , ed . Passive smoking and health research . New York : Nova Science Publishers , 2007 : 283–96 Purpose To vali date the dominant pulse sequence paradigm and limited role of dynamic contrast material -enhanced magnetic resonance ( MR ) imaging in the Prostate Imaging Reporting and Data System ( PI-RADS ) version 2 for prostate multiparametric MR imaging by using data from a multireader study . Material s and Methods This HIPAA-compliant retrospective interpretation of prospect ively acquired data was approved by the local ethics committee . Patients were treatment-naïve with endorectal coil 3-T multiparametric MR imaging . A total of 163 patients were evaluated , 110 with prostatectomy after multiparametric MR imaging and 53 with negative multiparametric MR imaging and systematic biopsy findings . Nine radiologists participated in this study and interpreted images in 58 patients , on average ( range , 56 - 60 patients ) . Lesions were detected with PI-RADS version 2 and were compared with whole-mount prostatectomy findings . Probability of cancer detection for overall , T2-weighted , and diffusion-weighted ( DW ) imaging PI-RADS scores was calculated in the peripheral zone ( PZ ) and transition zone ( TZ ) by using generalized estimating equations . To determine dominant pulse sequence and benefit of dynamic contrast-enhanced ( DCE ) imaging , odds ratios ( ORs ) were calculated as the ratio of odds of cancer of two consecutive scores by logistic regression . Results A total of 654 lesions ( 420 in the PZ ) were detected . The probability of cancer detection for PI-RADS category 2 , 3 , 4 , and 5 lesions was 15.7 % , 33.1 % , 70.5 % , and 90.7 % , respectively . DW imaging outperformed T2-weighted imaging in the PZ ( OR , 3.49 vs 2.45 ; P = .008 ) . T2-weighted imaging performed better but did not clearly outperform DW imaging in the TZ ( OR , 4.79 vs 3.77 ; P = .494 ) . Lesions classified as PI-RADS category 3 at DW MR imaging and as positive at DCE imaging in the PZ showed a higher probability of cancer detection than did DCE-negative PI-RADS category 3 lesions ( 67.8 % vs 40.0 % , P = .02 ) . The addition of DCE imaging to DW imaging in the PZ was beneficial ( OR , 2.0 ; P = .027 ) , with an increase in the probability of cancer detection of 15.7 % , 16.0 % , and 9.2 % for PI-RADS category 2 , 3 , and 4 lesions , respectively . Conclusion DW imaging outperforms T2-weighted imaging in the PZ ; T2-weighted imaging did not show a significant difference when compared with DW imaging in the TZ by PI-RADS version 2 criteria . The addition of DCE imaging to DW imaging scores in the PZ yields meaningful improvements in probability of cancer detection . © RSNA , 2017 An earlier incorrect version of this article appeared online . This article was corrected on July 27 , 2017 . Online supplemental material is available for this article Preamble Although economic outcomes research is an evolving field in health services research , there are correct and incorrect ways to conduct and report on economic outcomes studies . Research practice s that help to minimize real or perceived bias will increase the quality and usefulness of such studies for those who sponsor , publish , and use them . Because of public concerns about the potential for bias in the design , analysis , and reporting of economic analyses of health care technology , we formed a task force to develop principles to enhance the credibility of these studies . The Task Force on Principles for Economic Analysis of Health Care Technology included participants from academia , the pharmaceutical industry , the public sector , and private research organizations . As health care re sources become increasingly constrained , the information used to make re source allocation decisions must be as reliable , valid , and free of bias as possible . Getting it right at the level at which economic results are produced will help to protect consumers and will advance the health of the public . Bias stems from two broad categories : lack of appropriate independence for research ers and lack of consensus about methods . We focused heavily on the first of these categories for two major reasons . First , few have yet considered the unique issues of research er independence in economic outcomes research [ 1 , 2 ] . Second , other investigators have begun to consider and define proper methods for economic outcomes work ( an area of considerable controversy ) [ 3 - 5 ] . We also looked closely at the requirements for the reporting of economic analyses , which are intended to ensure method ologic transparency and accountability . The Need for Voluntary Guidelines Widespread use of economic analysis as part of the development of pharmaceutical , biotechnologic , and medical devices is relatively new . To date , many economic analyses of health care have focused on pharmaceutical agents , and many such studies have been funded by pharmaceutical companies . Results of these economic outcomes studies are used by medical technology firms to support the pricing and marketing of new interventions and to influence national health care systems and third-party payers in their development of coverage and payment decisions . Managed care organizations , hospitals , and government-subsidized health care programs rely on economic analysis of medical technology to help make formulary purchasing and utilization decisions . Physicians may use the results of these analyses to help guide treatment and prescription decisions . Health care economic outcomes projects are sponsored and conducted by pharmaceutical , biotechnologic , and medical device companies ; government agencies ; nonprofit foundations ; academic investigators ; and private research and consulting firms . The st and ards and methods used to evaluate the safety and efficacy of pharmaceutical products in r and omized , controlled trials have evolved over 50 years of collaboration among research ers in private , public , and academic setting s. Compared with those established to ensure the safety and efficacy of clinical trials , the principles and methods for the conduct of economic studies of health care technology are far less developed . Problems of conduct , reporting , and bias exist in all types of research [ 6 - 14 ] . In response , codes of conduct , such as those developed by the American Federation for Clinical Research and the Institute of Medicine , have been developed for many scientific disciplines [ 15 - 24 ] . These are good models on which to base principles of conduct for economic outcomes analysis . Although many published principles apply to economic studies , others should be modified and new ones should be developed to guide the conduct and reporting of economic outcomes analyses . Economic outcomes research requires unique guidelines for the following reasons : 1 ) As a field , it continues to evolve and is often misunderstood by end users ; 2 ) peer review of it requires special expertise that often exceeds the capabilities of review ers and scientific journals ; 3 ) it often uses secondary data and requires that many assumptions be made [ for example , attribution of a dollar cost to a unit of re source use ] ; 4 ) it offers unique method ologic choices , such as which types of costs to include ( direct , indirect , intangible , induced ) , which perspective to apply ( that of society , payer , provider , patient ) , which design to adopt ( cost- identification , costbenefit , cost-effectiveness , costutility ) , from where to obtain costs [ indemnity data base , managed care or capitated data base , hospital cost systems , Medicare , Medicaid ] , and whether to collect re source consumption data prospect ively or retrospectively through various modeling techniques ; and 5 ) economic studies play an increasingly important role in health care decision making because of increasing financial constraints throughout the health care industry . The financial and medical implication s of decision making done on the basis of these studies , coupled with the lack of widely accepted guidelines about the conduct and reporting of economic analyses , undermine the credibility of this research . A major issue is that the primary source of funding for this research is often the primary financial beneficiary of positive study results . Unfortunately , even valid studies done under the best of circumstances may be suspect [ 25 - 29 ] . This has led at least one major journal to conclude that these analyses should be viewed much like editorials or review articles are viewed in terms of potential for conflicts of interest [ 30 ] . We developed the guidelines reported here after extensive consultation with experts from the public , private , and academic sectors . We recommend that research ers and sponsors adhere to these guidelines , and we suggest they state publicly within their manuscripts that they have done so . End users , including journal editors and readers , consumers , and social decision makers , may then feel more secure in accepting the results of the research , while recognizing that intensive critique of the research will always be necessary . Operations of the Task Force The Task Force on Principles for Economic Analysis of Health Care Technology was initiated and organized by faculty from the Leonard Davis Institute ( LDI ) Center for Health Policy of the University of Pennsylvania . However , because not all LDI faculty were involved , this paper does not represent an official LDI position statement . The Task Force was funded by a coalition of pharmaceutical companies ( Appendix A ) . Funding was also requested ( but not obtained ) from various government and private foundations . All funding was provided in the form of unrestricted research grants or gifts to the University of Pennsylvania . Guidelines derive their credibility in part from the composition of the panel that creates them and the process by which they are developed . C and i date s for participation in the Task Force from the private sector and the academic research community were identified by the frequency with which they were cited in the health economics literature , which was obtained using a MEDLINE search of literature related to economic analyses of medical technology published between 1983 and 1992 . Approximately 15 members attended each meeting . Minutes were distributed after each meeting and approved by all members present . Members from the sponsoring pharmaceutical companies and the academic organizers rotated so that they numbered three and one , respectively , at the table for each formal Task Force meeting . Several professional and governmental organizations , including the Institute of Medicine , the Agency for Health Care Policy and Research , the Food and Drug Administration ( FDA ) , the Health Care Financing Administration , the Centers for Disease Control and Prevention , and a managed care organization , were asked to suggest persons who might participate . In addition , other organizations with a stake in economic analyses were each asked to suggest a person who , because of his or her professional background , had extensive knowledge of or experience with economic analyses . An academic pharmacist , an academic research er , a private research er , an ethicist and patient advocate , and an attorney specializing in medical ethics rounded out the Task Force ( Appendix B ) . Two members withdrew from participation . A small audience consisting of industry sponsors , academic organizers , staff , and a few other interested parties were invited to each meeting and allowed to comment . Four formal meetings of the Task Force were held in Philadelphia during 1993 and 1994 , and the most substantial work was done by various subcommittees between these meetings . The three main subcommittees were titled Ethical Conduct , Responsibility and Control ( the findings of these two subcommittees were later merged into one report ) , and Reporting Requirements for Economic Evaluations ( Appendix C ) . The Task Force was assisted by a professional facilitator . Although Task Force members sought consensus wherever possible on the key issues , consensus was not forced and recommendations were issued only when substantial agreement existed among the members . Task Force members were not asked to formally represent any organization . Formal endorsement of the final document was not sought . Copies of this report will be distributed to all organizations that were asked to suggest a participant and to other parties who responded to announcements placed in The New Engl and Journal of Medicine , Scrip , and the Pink Sheet . The Task Force findings will also be reported at academic conferences , medical profession meetings , and appropriate trade conventions . Findings and Recommendations Valid approaches to economic analyses can be defined ; acceptable methods can be differentiated from unacceptable ones . Bias in economic research stems from two major sources : lack of appropriate independence for
We found a continuing trend towards conducting DCEs across a broader range of countries .
However , the trend towards including fewer attributes was reversed , whilst the trend towards interview-based DCEs reversed because of increased computer administration .
The trend towards using more flexible econometric models , including mixed logit and latent class , has also continued .
Reporting of monetary values has fallen compared with earlier periods , but the proportion of studies estimating trade-offs between health outcomes and experience factors , or valuing outcomes in terms of utility scores , has increased , although use of odds ratios and probabilities has declined .
The reassuring trend towards the use of more flexible and appropriate DCE design s and econometric methods has been reinforced by the increased use of qualitative methods to inform DCE processes and results .
However , qualitative research methods are being used less often to inform attribute selection , which may make DCEs more susceptible to omitted variable bias if the decision framework is not known prior to the research project .
Background Discrete choice experiments ( DCEs ) are increasingly used in health economics to address a wide range of health policy-related concerns .
Objective Broadly adopting the methodology of an earlier systematic review of health-related DCEs , which covered the period 2001–2008 , we report whether earlier trends continued during 2009–2012 .