# shelf score interpretation

#### golgi

##### Senior Member
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Whats up,

quick Q regarding shelf score. the 2 digit score that we get from our school - is it the percentile or the actual score. If it's the actual score what percentile would an 80 on the shelf be?

Hope everyone had a great weekend! Back to surgery at 5 am tommorrow (yuck)...

#### kcrd

##### Playing doctor
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I don't think it's either percentage or percentile. The mean is set arbitrarily at 70 (or is it 75?), and you get a score relative to that.

#### dry dre

##### All hat, no cattle
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To the best of my knowledge:

The mean numerical score for each shelf exam is 70; the standard deviation is either 7 or 8.

Using the following table, a numerical score of 80 with a stand-dev of 8 would roughly equate to a percentile of 89.

All this may be wrong...

#### Vincristine

##### Full Member
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Interestingly enough, we get all sorts of information with our shelf scores, most of it is an actually an explaination from the NMBE. My sheet lists both a two digit score and the corresponding precentile. I am not sure, however, if I can interpret "my score" as the actual number out of 100 or not. The line "your score is expressed as a two-digit number." does not clarify any.

I believe the mean for most of the subject exams is about 70, but I am only looking at my surgery sheet right now. There are published (if your medical school does not provide this info to you, I don't know where to find it) "Norms for Examinee Performance" for each subject exam. This includes the mean and SD for the total year as well as broken down quarterly because people do better later in the year when we have more general knowledge. For instance, surgery: total year mean & SD = 69.9, 9.0. Qrt 1 (Aug-Oct) 67.4, 8.5. Qtr 2 (Nov-Jan) 69.4, 8.8. Qtr 3 (Feb-Apr) 71.3, 9.0. Qtr 4 (May-Jul) 71.6, 9.0. Also listed are the percentile ranks for each score (54 to "93 and above) for the total year and each quarter.

Sounds to me like unless your school tells you what they are giving you, there's no way to know. However, I would think it makes more sense for them to tell you your two digit score rather than your percentile.

#### Vincristine

##### Full Member
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Originally posted by kcrd
I don't think it's either percentage or percentile. The mean is set arbitrarily at 70 (or is it 75?), and you get a score relative to that.

According to the NMBE published "Norms for Examinee Performance" the mean and SD are actually CALCULATED for the given N and specific scores.

#### 12R34Y

##### Full Member
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I agree with one of the above posters............that you school (ie. professors) should be telling you exactly how to interpret these scores.

all the shelfs i have take they give us a very clear understanding of what we are receiving..

later

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