Step 1 Cutoffs

On my score report sheet from this past June, it lists the mean as 216, and the standard deviation as 24...so that makes 240 about the 85th percentile.

To complement all the good info above:

If you want to know percentile rank for a normal distribution (we have to assume the USMLE scores are close to normal... which is probably true), calculate a Z score.

Z = ((Your Score)-(Mean Score))/(Standard Deviation)

You can then look up the correlation between Z score and percentile in Z score tables like this one:



For example, If your score was 248, the mean was 215 and the standard deviation was 15, then:

Z=(248-215)/15 or Z=2.2

Based on the table, a Z of 2.2 corresponds to a percentile rank of 98.6%

And, as stated by those above, a Z score of 1 (1 standard deviation above the mean) corresponds to 84%, and a Z of 2 corresponds to 98%

Again, this assumes a normal distribution, but it should be close for the USMLE.

By the way, does anyone know to what the 2 digit score corresponds? I know that at least a few programs pay the most attention to this score (or so I've heard from a couple P.D.'s). Near as I could figure when I took the test, any one with a Z > ~ 1.5 got a 99, but that is based on a few conversations with a few people.

actually, to be a little more precise, doing 1 SD above the mean means you did better than 84% of the people taking the test. This is because the mean corresponds to doing better than 50% of the people, and 1 SD is 34% better than that (1 SD above and 1 SD below mean equals 68%, which is 34% above and 34% below mean). Likewise, if your score is 2 SDs better than the mean, you are in the top 2.5%, not 5%.

the 93 is not a percentile. This is a common misperception about USMLE scores! To get an idea of how you did compared with others, look at the Standard deviation ..if mean is 215 and SD is 10, then a score of 235 means you did better than 95% of those taking the exam (2 SD above mean). Likewise, a score of 195 (2 SD below mean) means only 5% of examinees did worse than you did. One standard deviation above/below mean covers about 68% of examinees. So with a mean of 215 and SD of 10, a score of 225 means you did better than 68% of examinees, but worse than 32%.

If you read your score report, it will tell you that the 2-digit number is not a percentile. But they give you the mean and standard deviation so you can get a sense of how your performance compares to others. It's a bell-shaped curve with normal distribution.

I took step I about a year ago and I got a 229 which correlated to a 93%, I hope that gives you guys an idea.

Your percentile will correspond with what other people got during the block of time (which I don't know how they break down) you took step I.

It has been about 5 years since I took step one, but 242 seems high for the 85th percentile. I think when I took it 85th percentile (roughly one Standard Dev above the mean) was 235.

what were the average and sdev for the step 1 given this past summer?