Reducing research waste by promoting informed responses to invitations to participate in clinical trials.

Poor recruitment to, and retention in, clinical trials is a source of research waste that could be reduced by more informed choices about participation. Barriers to effective recruitment and retention can be wide-ranging but relevance of the questions being addressed by trials and the outcomes that they are assessing are key for potential participants. Decisions about trial participation should be informed by general and trial-specific information and by considering broader assessments of 'informedness' and how they impact on both recruitment and retention. We suggest that more informed decisions about trial participation should encourage personally appropriate decisions, increase recruitment and retention, and reduce research waste and increase its value.