Does any one know how the curve works for scoring? Are you curved against people who took it the same day as you, or is it an aggregate of all the scores thus far for the form you had?
Two possibilities:
1)
People get identical exams.
For instance, there could be 25 potential 322-question forms out there that are all scaled against one another so that their difficulties are comparable, and then people taking identical forms are scaled against each other.
2)
People are allocated identical blocks.
For instance, there could be 175 potential blocks out there (if we assume that there are 25 different 322-question forms), where all blocks are scaled against one another to establish comparable difficulty, and then each person, with his or her different 7-block combinations, has scaled scores from each block that are averaged to derive the 3-digit score.
My guess is that people get entire identical exams.
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In the past, I had always thought that people get a random allocation of 322 questions from some massive database, but that can't be the case. How do I know that?
Although we are not supposed to talk about specifics from our exams, I had been emailed by a person who had taken his/her exam about a month after I had, where he/she had asked me about particular things that had shown up for clarification purposes, and we both shared four WTF questions on our Step1,
where two of those four were roughly ten questions apart in the 5th block, and a third was during the 6th block.
Given the 5th block information, that supports hypothesis #2 above. However given the information overall, hypothesis #1 gains likelihood.
I believe this student and I probably had whole-exam raw scores that were compared against each other and scaled on a time-independent analysis scheme in order to derive our 3-digit outcomes.
New NBME exams likely reflect retired whole-exams. Repeat questions on current actual exams from previous NBMEs indicate that although people get duplicate whole-exams,
a few of the questions are shared between forms.