Reliability of the New NBME Forms in Predicting USMLE Step 1 Score

This blog was originally posted on February 23, 2021 and updated on July 11th, 2023. For our updated reviews of the best predictors for passing Step 1 see NBME 25- NBME 30: Which is the Best Predictor for Passing Step 1. Original post:

Predict the USMLE Step 1 Score with NBME Score

If you weren’t aware, the NBME will be retiring CBSSA Step 1 Forms 18, 20, 21, 22, 23, and 24 on March 2nd, 2021.  On the same day, NBME will release 6 new NBME Step 1 practice exams, Forms 25, 26, 27, 28, 29, and 30.

Whenever we speak with students about preparing for the USMLE Step 1, we tell them that first, we need to get a baseline performance and then we need to measure their performance at regular intervals. However, many students are afraid to check themselves because they don’t want to be disappointed.

There is an additional problem that comes up when discussing predicted score performance on the USMLE Step 1: 

Which NBME form is the best for predicting my actual score on the USMLE Step 1? 

And now that many of the existing forms will be retired, and 5 new ones will replace them, the question becomes:

How good will the new NBME forms be at predicting my actual score on the USMLE Step 1?   

Because the scoring system for the USMLE Step 1 (and by extension the NBME CBSSA) is essentially a black box, we cannot know for sure how predictive these exams will be. 

In our experience however, all of the currently available forms, and even many of the long retired older forms, remain excellent predictors of USMLE Step 1 score performance. At the end of the day, medicine is medicine, and for the Step 1 student, not that much has actually changed over the years beyond a few additional medications. Note: This isn’t necessarily the case for Step 2 CK, which tests management and treatment guidelines that do change over time. This notion makes it particularly exciting that NBME will also be releasing new Step 2CK NBMEs sometime in 2021.

For USMLE Step 1 students, it can feel as though so much new information has been added.  More likely, as students have become more attuned to the information mentioned on the test, they have compiled ever greater lists of topics, terms, diseases, etc that they may have seen.  However, just because a particular rare disease was listed as an answer choice on a real Step question does NOT mean that the disease itself was (or will ever be) explicitly tested.

So, what is the bottom line?  

• We don’t yet know what the accuracy of the new NBME Forms will be.
• However, we expect that the new NBMEs will strive do an even better job at score prediction than the forms being retired.  
• New Step 2CK forms are also coming in 2021
• Check back for more updates!

In the end, using the old forms or the new forms solely for score prediction is a poor use of a valuable Step 1 learning resource.

GOOD LUCK! And as always, if you find yourself in need of a USMLE tutor, contact Elite Medical Prep for help!