Completely wrong. Per the NBME website:
"
What has been said:
I have heard that if you take Step 1 in May through July, you will get a lower score or fail because a lot of candidates test during this period and competition is high.
Reality check:
Fiction
Explanation: The USMLE uses statistical techniques called
equating to ensure that the 3-digit score is comparable regardless of what test form or what time of year a candidate tests. There are, however, natural ebbs and flows to the preparation, readiness, and demographic composition that may be associated with the success of candidates who take or retake Step 1 at particular times of the year, which can lead to modest variations in pass rates. For example, specific, highly selective US medical schools whose students typically have very high pass rates tend to test within specific time bands associated with their curriculum, resulting in somewhat higher pass rates during this period. In contrast, students who were unsuccessful on their first attempt tend to retake at other times of the year, resulting in somewhat higher fail rates at that time of year. The statistical techniques used ensure that the same standard is applied to all students regardless of what time of year they test or what test form they are administered."
What this means is that they DON'T just normalize you to the people you take the test with. You are compared to all previous years, which means if everyone during a certain period scores extremely high percentages then they will all get extremely high scores. The difficulty of questions must either be determined (1)
a priori, or (2)in a manner combining current and historical data for each question. Remember, the NBME doesn't make all new questions each year, which is why they have a good idea of how current tests compare to previous ones...