Factors influencing subject willingness to participate in clinical gerontologic research.

To identify factors influencing willingness to participate (WTP) in clinical gerontologic research, a questionnaire containing descriptions of seven research projects with a corresponding set of questions about perceived intrusiveness (discomfort and inconvenience), stipend, and other incentive factors was sent to 1004 community-dwelling research subject registry members. There was an inverse relationship between perceived level of intrusiveness and WTP. The more intrusive the study, the greater the relative influence of a stipend on WTP. Male gender and a new experience with an opportunity to learn were independently related to WTP. Subject ratings of perceived intrusiveness for each study component were entered into a factor analysis to guide the development of a three-tier "Level of Intrusiveness" scale. Although prospective validation is necessary, the Level of Intrusiveness scale may be useful in predicting WTP, and determining when other incentives are needed to improve subject recruitment for clinical research.