How Predictive Is CBSE for Step 1?

CBSE has been submitted to Predict My Step Score 15,983 times and tracked against the real Step 1 results students went on to report. In that data, CBSE was a strong pass signal — well ahead of a coin flip.

What is CBSE?

The CBSE (Comprehensive Basic Science Exam) is an NBME exam that medical schools administer themselves, usually as a benchmark before dedicated study or as a requirement to sit Step 1. It covers the same content as Step 1 and reports an equated percent correct, so it behaves like a proctored NBME form taken earlier in the year.

What is a good CBSE score?

In our data, CBSE scores ranged from 34% to 92%. Since Step 1 is pass/fail, there is no target number to hit: a "good" CBSE score is one that sits comfortably inside the range where passing was the norm for students in our data, with enough margin that one rough block on the day would not put you at risk.

When should you take CBSE?

The CBSE is usually scheduled by your school rather than by you, often before dedicated study begins; use it to see where you stand with the whole study period still ahead.

Does it matter when you take CBSE?

Timing matters twice over. First, a score from six weeks out is a snapshot of a student who then kept studying, so early tests tend to sit below the real result — much of what looks like "underprediction" is simply improvement after the test. Second, our predictor does not treat every score you enter equally: each one is weighted by the exam's R² and by how recently you took it, with a recency factor that decays exponentially from your most recent test back to your oldest, and your three most recent scores drive the final adjustment. Enter the days-before-exam for each test honestly — it changes the answer.

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CBSE score

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Takes you to the predictor with CBSE already filled in — add your other practice exams there for the full prediction.

How CBSE compares

Wondering whether to take CBSE next? See which practice tests are most predictive.

Frequently asked

Is CBSE accurate?

In our data CBSE was a strong pass signal — well ahead of a coin flip. No single practice test settles pass/fail on its own, though — combining your scores, weighted by each exam's track record and timing, gives a much better read than any one sitting. Predict your Step 1 score →

Does CBSE overpredict or underpredict Step 1?

Step 1 is pass/fail, so there is no point bias to report. In our data CBSE was a strong pass signal — well ahead of a coin flip.

Is CBSE or UWSA 1 more predictive?

UWSA 1 is more predictive in our data. The exact gap is part of the full ranking, which is available to premium users.

Where does this data come from?

15,983 CBSE scores have been submitted to Predict My Step Score so far. Whenever a student also reports their actual Step 1 result, the pair goes into the model behind this page; it was last refit on 2026-05-14.

Can't I just ask ChatGPT how predictive CBSE is?

Not reliably. A prediction is only as good as the paired data behind it: real CBSE scores matched to the real Step 1 result those same students went on to get. General-purpose AI models are trained on forum posts and articles, not on verified outcomes, so what you get back is a summary of anecdotes rather than a calibrated estimate. The numbers on this page come from students who reported both. Read more →

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Data refreshed 2026-05-14.

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