what does shelf socre mean?

[iamhotok]

---

Members don't see this ad.

if one get a score, what does it mean?
what is the national average?

 

[Stinger86]

it depends on the particular shelf exam. When you get your score back, ask the dean or whoever of your med school what the national average on the shelf was as reported by the nbme. It should be included in the results that are sent back to your school

 

[Discobolus]

My understanding is that the National average is always 70, because that is how the test is curved. The National average is set as 70 with a standard deviation of 8 points. What will change from test to test though is the distribution of scores, so the percentile for a given score may change from test to test. You should be able to get this information from the course directors. For example on the biochemistry exam a 76 was 68th percentile, but on the physiology exam a 76 was 79th percentile.

 

[beriberi]

The clinical shelves give you a number right (out of 100) and a percentile.

The average is 50th percentile (that is the nature of percentile). Passing (at my school) is 10th percentile--usually around 60% right.

I don't know how you can curve the number of questions right to be 70 (because you certainly cannot 'curve' a percentile to make the average 70--percentiles are always curved to start out with).

 

[Discobolus]

70 isn't a number right, percentage correct, or percentile, it's just a number. No different really than a 30 on the MCAT which in itself doesn't mean a thing. I think a lot of people get confused about the raw score on the shelf exams because they think it's a percentage or a percentile when it's neither, it's just a number. The information about the scoring of the NBME shelf exams in on the NBME website.

 

[Stinger86]

70 isn't a number right, percentage correct, or percentile, it's just a number. No different really than a 30 on the MCAT which in itself doesn't mean a thing. I think a lot of people get confused about the raw score on the shelf exams because they think it's a percentage or a percentile when it's neither, it's just a number. The information about the scoring of the NBME shelf exams in on the NBME website.

Yep, that's why knowing the national average for a particular exam is much more informative

 

[iamhotok]

so i still don't know what it means.

is it true then there are around 50% students nationwide that have scores less than 70?

 

[Discobolus]

so i still don't know what it means.

is it true then there are around 50% students nationwide that have scores less than 70?

All depends on the score distribution for the test. Remember 70 is the mean not the median. With a normal distribution they would be the same but the shelf exams don't seem to have normal curves, so it changes from test to test. On the biochemistry shelf a 70 was 38th percentile, while the neuroscience shelf a 70 was 55th percentile.

 

[iamhotok]

what exactly is percentile?
if that 70 is 38 percentile, does that mean 38% have 70 or above, and rest are below 70?

 

[Discobolus]

percentile is the % of people who took the test who are below a given score, so the higher the percentile the better the score.

In the case of the 38th percentile for a 70 on the shelf exam that means 38% of the test takers scored below a 70. 70 is still the average in this case because the distribution of scores did not follow a normal curve. If there had been a normal bell shaped curve of scores the average (set as 70) would have also been the 50th percentile.