BACKGROUND ESSENTIAL TO THE PROPER USE OF RESULTS OF STEP-1 AND STEP-2 OF THE USMLE

This first of the four-part set of articles published in this issue pr ovides general information and concepts about the Step 1 and Step 2 ex aminations of the United States Medical Licensing Examination (USMLE) needed for the proper use of these tests' results in three general, re lated, non-licensure applications: for the evaluation of the examinees ' levels of academic achievement, for the evaluation of educational pr ograms the examinees have experienced, and for the selection of examin ees into residency programs. Several aspects of the tests are discusse d: (1) their original and continuing purpose (which is to assess certa in qualifications required for licensure of physicians); (2) their con tent; (3) their format and the emphases (relative to knowledge or skil ls testing) that different formats can give, and the concept that the ways the same content areas are formatted in a test will produce diffe rent results; (4) test administration, with a discussion of ''speeded' ' versus ''power'' tests and the organization of test items by difficu lty and by (or not by) topic; (5) reliability, with a discussion of st andard error and the importance of understanding measurement error in order to discern real differences in scores; (6) scoring, with definit ion of anchor scores; and (7) interpretation, with discussions of pass /fail criteria in the past, present, and future of the USMLE tests. Th e authors close by saying that to interpret test performance properly, it is important not only to bear in mind the ideas in the present art icle but also to carefully review an actual test or at least a represe ntative sample of test questions.