Findings that informed feasibility assessment where progression criteria were not stipulated
RECRUITMENT
Of the 34 respondents who had authored external pilot trial publications that did not include progression criteria (surveys 3 and 4), 32 (32/34, 94%) provided details about the findings they considered when determining feasibility, see Table The most frequent consideration was also qualitative research findings (17/32, 53%). Fourteen respondents described that recruitment had informed their assessment of trial feasibility (14/32, 44%), such as considering the recruitment rate, recruitment processes, consent rate, and timeframe associated with recruitment. Ten respondents considered whether there was any indication of efficacy or effectiveness when deciding whether a definitive trial was feasible (10/32, 31%). Ten respondents described considering findings in relation to the definitive trial design (10/32, 31%). For example, whether the sample size required for the definitive trial was achievable and the methods of data collection. Nine respondents described considering retention or attrition when determining feasibility (9/32, 28%), and nine described considering whether there was sufficient interest, acceptability or uptake of intervention (9/32, 28%) including intervention adherence or engagement, completion or withdrawal rates, and willingness to be randomised. Seven respondents described considering whether the intervention could be implemented (7/32, 22%; for example deliverability and intervention fidelity), and four described considering implementation of the trial (4/32, 13%; for example, resources and sites required, willingness of healthcare providers to implement the study and acceptability of study procedures).