The introduction of a clinical skills examination (CSE) to Step 2 of the U.S. Medical Licensing Examination (USMLE) has focused attention on the design and delivery of large-scale standardized tests of clinical skills and raised the question of the appropriateness of evaluation of these competencies across the span of a physician's career. This initiative coincides with growing pressure to periodically assess the continued competence of physicians in practice. The USMLE CSE is designed to certify that candidates have the basic clinical skills required for the safe and effective practice of medicine in the supervised environment of postgraduate training. These include history taking, physical examination, effective communication with patients and other members of the health care team, and clear and accurate documentation of diagnostic impressions and plans for further assessment. The USMLE CSE does not assess procedural skills. As physicians progress through training and enter practice, both knowledge base and requisite technical skills become more diverse. A variety of indirect and direct measures are available for evaluating physicians, but, at present, no single method permits high-stake inferences about clinical skills. Systematic and standardized assessments make a contribution to comprehensive evaluations, but they retain an element of assessing capacity rather than authentic performance in practice. Much work is needed to identify the optimal combination of methods to be employed in support of programs to ensure maintenance of competence of practicing physicians.