Quote:
Originally Posted by Guile
I'm not sure why that is the case if the average is set to be 70 and the SD 8 for each testing. Wouldn't that lock in the percentiles? I think that it just means that an 80 late in the year means more than an 80 early in the year.
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The reason the percentiles aren't "locked in" is because the exam isn't standardized to a mean of 70/standard deviation of 8 for each testing. Those numbers are based on, as the NBME puts it, "a scaling group of first-time takers from U.S. LCME-accredited medical schools who took this examination as a final clerkship examination under standard testing conditions." According to the NBME website, that group took the exam during the 1993-94 academic year. Presumably, like USMLE scores, students' shelf scores are increasing as schools admit more competitive applicants and students study more.