sNATIONAL BOARD OF MEDICAL EXAMINERS
Subject Examination Program
Comprehensive Clinical Science Examination
Score Interpretation Guide
NBME subject examinations provide medical schools with a tool for measuring students' understanding of the clinical sciences. While subject examinations are designed to be appropriate for use by most medical schools, curricular objectives vary, and the congruence between subject examination content and curricular objectives should be considered in the interpretation of test scores and in the determination of grading and promotion standards. NBME neither sets nor recommends a “passing” score. Subject examination scores should not be used alone, but rather in conjunction with other indicators of student performance.
Subject Examination Scores
The subject examination score on the Comprehensive Clinical Science Examination (CCSE) is scaled so that a score of 70 on the CCSE is approximately equivalent to a score of 200 on USMLE® Step 2 Clinical Knowledge (CK). The vast majority of scores range from 45 to 95, and although the scores have the "look and feel" of percent-correct scores, they are not. Because the CCSE and USMLE Step 2 CK cover similar content, this scale provides a useful tool for comparing the scores of your students with those of a large, nationally representative group taking the licensing exam in their final year of medical school. Additional information about the relationship between CCSE scores and USMLE Step 2 CK scores is provided in the table on the next page.
Unlike percent-correct scores, subject examination scores on the CCSE are statistically equated across test administrations. As a result, these scores can be used to track student performance over time.
Precision of Scores
Measurement error is present on all tests, and the standard error of measurement (SEM) provides an index of the (im)precision of scores. The SEM indicates how far the score a student earns on the examination is likely to stray from his/her “true” proficiency level. The SEM is approximately 4 points for the CCSE scores. Using the SEM, it is possible to calculate a score interval that indicates how much a score might vary across repeated testing using different sets of items covering the same content. An interval that will encompass about two thirds of the observed scores for a given true score may be found by adding the SEM to a score and subtracting it from that score. For example, if a student’s true proficiency on the examination is 60, the score he/she achieved on the examination will usually (two times out of three) fall between 56 and 64 (60 - 4 and 60 + 4).
Score Feedback
Summary information on the examinee group tested, exam purpose and number of items scored is provided on each page of the feedback.
If two or more examinees were tested, Scaled Score Descriptive Statistics for reported scores, including the mean, standard deviation, the lowest and highest scores for the examinees tested is provided.
The Roster of Scaled Scores reports a total test CCSE score and content area subscores (when available) for each examinee. Reported scores also appear in a comma separated text file that can be downloaded and used to export scores.
If two or more examinees were tested, a Frequency Distribution of the total scaled score is provided. The distribution shows the number and percentage of examinees with each score, together with the cumulative frequency and percentage.
Keyword Phrase Item Analysis
If ten or more students were tested, a Keyword Phrase Item Analysis Report is provided. This report provides a keyword phrase describing the content of each item on the examination, along with the proportion of the examinees from your school and a projected proportion of examinees nationally that answered each item correctly.