In your score report you will see what's called SEM which stands for the standard error of measurement. This is an index of the variation of scores that would be expected to occur if an examinee was tested repeatedly using different sets of questions. The current SEM is 5 to 8 points (on the three digits scale
This means that "luck" is exactly accounting for this degree of variation only.
So if you yourself, take the exam the next day and given a completely different 336 questions, you will still get the same score within the range specified above.
So luck has a very minor role in USMLE exams.
Then how come we have different scores among two students that have read the same materials and have got similar USMLE World or NBME scores?
Here is a list of the potential reasons for this observed difference:
- Some people are not honest. They tell you that they have studied but they did not or they falsify their UWorld score or they give their score after doing the questions three and four times.
- Reading is not the same reading with everyone. Some people they read just like a newspaper without retaining anything and without paying attention to details. USMLE exam preparation needs somebody who's alert and astute. You have to be vigilant and on the lookout. You have to understand the concepts behind the high yield topics and not just memorize few points here and there.
- Some people have very poor exam taking strategy like they panic easily or they don't know how to exclude wrong answers to reach the correct one or they have poor concentration or they don't read the question carefully
- The exam needs some IQ. Some students have gone to med school by chance and they don't have enough IQ and mental power to tackle such a large comprehensive tricky exam.
If you have read your materials carefully and if you are scoring above 60% in UWorld or Kaplan QBank (first attempt) or any other major Qbank and if you pass the NBME
I guarantee for you that you will pass the USMLE exam with a wide margin of safety.