This report of the development and validation of a criterion-referenced examination for physician's assistants contains an overview of phase 1 project activities (1972-74) and more detailed description and data on phase 2 activities (1975-76). The overview describes the rationale for the development of the examination. (It was the first certifying examination for health care professionals that was based on task analyses of health care functions--data gathering, analysis and interpretation, and medical and health care strategies--as opposed to curricular content.) Administration of the first National Certifying Examination for Primary Health Care Physician's Assistants in 1973, the validation studies of that exam, and the administration and statistical analyses of the 1974 exam are summarized in the overview. Phase 2 activities are described in detail in three sections: (1) A study of audiovisual simulation techniques for assessing interpersonal skills, (2) a validation study of the 1974 certifying examination involving medical record audits, and (3) an analysis of the 1975 certifying examination. Appendixes A, B, and C contain the audiovisual simulation materials which include the sample paper-pencil simulation, the interaction observation form, and the patient protocol form. Appendixes D and E contain the audit validation study materials, which include the sample audit criteria set and the instruction manual and sample abstracting form for record reviewers. References are provided. (TA)