Many factors can affect the successful implementation and validity of intervention studies. A primary purpose of feasibility and pilot studies is to assess the potential for successful implementation of the proposed main intervention studies and to reduce threats to the validity of these studies. This article describes a typology to guide the aims of feasibility and pilot studies designed to support the development of randomized controlled trials and provides an example of the studies underlying the development of one rehabilitation trial. The purpose of most feasibility and pilot studies should be to describe information and evidence related to the successful implementation and validity of a planned main trial. Null hypothesis significance testing is not appropriate for these studies unless the sample size is properly powered. The primary tests of the intervention effectiveness hypotheses should occur in the main study, not in the studies that are serving as feasibility or pilot studies.

Objective. The relationships between clinical outcomes and predictors used to screen applicants for entrance into a Master in Occupational Therapy (MOT) program were examined. Method. MOT student records from 1986 to 1992 were used to gather data for three dependent variables and six predictor (independent) variables. The dependent variables used to gauge student success were grade point average in occupational therapy courses (OT-GPA), client attendance at an on-site clinic, and therapy outcomes of clients at that clinic. The predictor variables were undergraduate GPA, scores on the three sections of the Graduate Record Examination, reference forms, and essays. Results. The models used to predict OT-GPA and therapy outcomes were significant (p < .05), and the incremental validity of several predictors was established. The model used to predict client attendance was not significant. Conclusion. The findings regarding OT-GPA support the continued use of all the predictors except the reference forms. Although it was possible to develop a model to predict client outcomes, the usefulness of the model is difficult to interpret.