Home » NBME 25- NBME 30: Which is the Best Predictor for Passing Step 1

NBME 25- NBME 30: Which is the Best Predictor for Passing Step 1

7 min


Medical students taking their USMLE Step 1 exam in a classroom.


There are an incredible number of resources out there for Step 1 preparation. No one study approach will work for everyone or guarantee success. Whatever plan or resources you decide to use, everyone will need to use practice questions and practice exams. These help to really gauge how well they understand the content that will be tested on Step 1. In this post, we will review the NBME 25 and 30 to help you understand which of these is the best predictor for passing USMLE Step 1. We recommend taking a look at our 10-Week Step 1 schedule or our 6-week Step 1 schedule to help you get on your way to Step 1 success!

Practice exams are one of, if not the most important factor of your Step 1 preparation. They provide a benchmark of how you are performing. Practice exams can also help you predict whether you are ready to take your exam. They are also very useful for breaking down your performance by subject area. This can help you identify areas where you might need to focus your studying. Taking all your practice exams seriously and thoroughly reviewing them is essential to your preparation for Step 1. You will get experience with the types of questions the USMLE will ask and review much of the content that could be covered on your exam.


Which Practice Exams are Available?


There are currently six practice exams offered by the National Board of Medical Examiners (NBME) for Step 1. These are called Comprehensive Basic Science Self-Assessments (CBSSAs). The current forms available to students for purchase are Form 25 – Form 30. Each exam is $60, however, your medical school may provide you with vouchers to take to one or more of these practice forms.

Each exam consists of four sections of 50 questions with a total of 200 multiple-choice questions. You can take each exam at a standard pace (1 hour and 15 minutes per section) or self-paced (5 hours per section). I recommend all my students use standard pacing in order to simulate the timing of the actual USMLE. In addition to the NBME exams, there are two UWorld Self-Assessments (UWSA) that are also good resources. If you want even more practice questions, the NBME also offers a Step 1 Orientation that includes 120 practice questions. This is known to many students as the “Free 120”. These questions are also similar to the style you will see on the USMLE, however, there are no official answer explanations to help you review the questions.


Which NBME Practice Exam is the Best Predictor for Passing Step 1?


Students often want to know which CBSSA is the best predictor for passing Step 1 This is especially important if you may not have enough time to take all the CBSSAs. Many students ask, “Which is the most important NBME?” or “How do I decide which NBMEs to take?”

Based on informal student reporting, NBME 28 and UWSA 2 are the most correlated with Step 1 performance. Given this information, it might be a good idea to take these two exams when you are further along in your dedicated study and closer to your actual test day. However, all the CBSSAs that are currently available as well as the UWSAs should be helpful predictors of your performance.

The NBME consistently updates the available test forms. The questions are reflective of the style and content that you will see on the USMLE Step 1. When you take a CBSSA, you will receive an estimate of your likelihood to pass Step 1 if you took it within a week of your practice exam. While many factors can affect your actual performance on test day, it is generally good for most students to have taken at least 3 practice tests and obtained a 95 percent or greater likelihood of passing before sitting for Step 1. 

Tutoring is a very helpful adjunct to Step 1 preparation. A tutor can help you decide which practice exams to take and when to take them. They can also help with creating an ideal study schedule, improving your test-taking strategy, and motivating you to help achieve success on USMLE Step 1. Schedule your complimentary consultation today to hear more about what we can do to help you succeed!

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About the Author

Kathleen Oakes

Katie has extensive experience tutoring at all levels in various subjects throughout college and medical school, as well as experience helping students with standardized test…

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