Mixed methods use observational evidence of index and downstream proce- dures, hospitalization, and drug costs and apply cost weights to estimate cumulative costs,128 130 whereas decision analytic models simulate clinical and financial data.131 137 Regardless of the approach, inherent assumptions and uncertainties with regard to the data and incomplete consideration of risks and benefits require that such calculations be considered as In most studies, stress imaging is estimated to provide a benefit over exercise ECG at a reasonable cost, commensu- rate with accepted values for cost effectiveness (ie, at the threshold for economic efficiency of ,$50 000 per added year of life), a result driven primarily by more frequent angiography and adverse cardiovascular events for those with a negative exercise ECG. Results of decision analytic and mixed modeling approaches comparing stress echocardiogra- phy with myocardial perfusion SPECT vary, with some favoring exercise echocardiography and others favoring ex- ercise nuclear MPI.128,133 The patient s pretest likelihood of CAD also influences cost-effectiveness such that exercise echocardiography is more cost-effective in lower-risk patients (with annual risk of death or MI ,2%) than in higher-risk patients, in whom nuclear MPI is more cost-effective. Use of invasive coronary angiography as a first test is not cost-effective in patients with a pretest probability ,75%.139,140 Finally, it is important to note that as the reimbursement for stress imaging decreases (it is now less than half the value used in older studies), the relative cost-effectiveness (dollars/quality-adjusted life-year saved) of stress imaging is more favorable than that of exercise ECG, and the comparative advantage of lower- to higher-cost imaging procedures is minimized. 