How to Use the NBME Self-Assessments to Prepare for Step 1

Despite their nondescript name, the Comprehensive Basic Science Self-Assessments (CBSSAs) offered by the National Board of Medical Examiners’ (NBME) cover material most closely related to the USMLE Step 1 exam. Consequently, they represent one of the most important resources to use to prepare for Step 1, yet many students aren't sure how to best utilize these practice tests, often referred to as "NBMEs".

Below is a comprehensive guide on how get the most out of these crucial practice tests in order to help you survive (and ace!) Step 1.

The Basics


As of today, there are 6 practice exams available under the Comprehensive Basic Science Self-Assessment (CBSSA) tab on the NBME website. Each exam costs $60 and can be purchased through the official website. Available forms include 13, 15, 16, 17, 18 and 19, with the missing numbers corresponding to “retired” exams. Older exams are no longer available through the NBME. but can be found online through unofficial websites. Don't feel compelled to seek out these retired exams; most students (including those who do excel on Step 1) don't use these old exams.


The format of these practice exams differs from the actual Step 1 exam in two key ways. First. NBME practice exams are comprised of 4 sections composed of 50 questions each. With 1 minute and 30 seconds theoretically allotted to each question, you have 1 hour and 15 minutes to complete each section and 5 hours total for the whole exam. The actual Step 1 exam is comprised of 7 sections of 40 question blocks, corresponding to 1 hour per section (7 hours total). Second, the user interface of the NBME practice exams is different from that of the actual exam, despite originating from the “official” organization, the NBME. Surprisingly, the UWorld question banks and practice exams best recapitulate the actual testing interface.

Taking the Self-Assessment


The exact timing of the first practice exam can be a contentious issue. Some argue that it should be taken at the very beginning, right before your dedicated study time. On the one hand, doing very poorly (or even failing) such an early exam can provide for a very motivated beginning to your studying. Additionally, it could give you a sense of which areas you are weak on. On the other hand, some argue that it is a “waste” of one of six crucial study aides, but this only holds true if the exam is not properly reviewed afterwards. Personally, I did not take an exam at the very beginning of my dedicated study period, ascribing to the latter rationale. Instead I took the first practice exam right after my first pass of First Aid.