NBME 31 Curve: Easier or Harder Than NBME 30?
A direct comparison of the NBME 31 score curve vs NBME 30. Question style differences, predictive accuracy, and when to take which form.
NBME 31 sits awkwardly between NBME 30 (slightly older, well-studied) and NBME 32 (newest, most predictive). Here's what makes the NBME 31 curve different and when it deserves a slot in your prep.
Perceived vs actual difficulty
NBME 31 feels slightly easier than NBME 30 in the moment — vignettes are a touch shorter, the most extreme curveball questions are absent. But the curve compensates: a raw score that would yield 245 on NBME 30 maps to roughly 248 on NBME 31. Net effect: similar predicted score, easier test-taking experience.
Predictive accuracy
- NBME 30: under-predicts real Step 2 CK by ~4 points
- NBME 31: under-predicts by ~3.5 points (closer to actual)
- NBME 32: under-predicts by ~2.5 points (closest to actual)
When NBME 31 is the right pick
Take NBME 31 about 2 weeks before test day, after you've taken NBME 30 (4 weeks out) and before NBME 32 (1 week out). It's a strong middle checkpoint — accurate enough to trust, distinct enough from NBME 32 that you're not just repeating yourself.
If you can only afford two NBMEs, skip NBME 31 and take NBME 32 + Free 120. The newer and more predictive forms give you more signal per dollar.
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