Preliminary development of a questionnaire measuring patient views of participation in clinical trials.

A total of 53 patients were recruited for the pilot study and 55 were recruited for the main study, substantially below the goal of 100 participants. Factor analysis revealed six factors measuring aspects of patients' perceptions of participating in clinical trials, including motivation, risks and benefits, the nature of the trial itself, and practical considerations, such as cost and convenience. Inter-scale correlations ranged between 0.06 and 0.64, indicating acceptable scale independence. Reliability scores (Cronbach's alphas) ranged from 0.62 to 0.85. Factor analysis results were somewhat unstable, with shared variance for several items across scales. This is likely due to the small sample sizes. In larger, more diverse patient samples, this questionnaire can be useful for measuring and incorporating patients' views into the design and execution of clinical trials.