Validity of certification measures for occupational therapists.

Major factors that can affect the results of validation studies are identified and include reliability, homogeneity of sample, and criterion contamination. An overview and a description of content, predictive, concurrent, and construct validities are presented as well as a review of the recent studies of the validity of the Field Work Performance Report and the Certification Examination for Occupational Therapists. Adequate evidence of content and concurrent validity has been established for the Field Work Performance Report, although evidence for long-range predictive validity is lacking. Content validity alone has been established for the Certification Examination for Occupational Therapists. The evidence indicates that the instruments should not be abandoned, that they are better than no measures at all. The directions research might take in the future are given and the implications of continued use of the instruments are evaluated.