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.