In service exam - why is my overall percentile less than the subsections?

[RadOnc2013]

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[radiaterMike]

Maybe overall percentile includes biology and physics?


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[RadOnc2013]

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[evilbooyaa]

One last question for today. Just trying to figure out where to optimize my time with only a month till the exams. On the 2017 in service, my overall percentile ranking was significantly lower than my percentile on any of the subsections. Does anyone know why this might be? I don't wanna say exsactly what mine were, but say the only three subsections for clinical were 1) H&N (and I get 20th percentile) 2) lung (and I get 60th percentile) and 3) gyn (and I get 50th percentile.). Why would my overall percentile be 10th? Is perhaps the overall percentile against only those in your PGY level, while each subsection is against all the test takers?

I highly doubt the bolded. Otherwise my percentile rank for individual subsections wouldn't make sense if it was going against all Rad Onc residents (rather than just those in my PGY level)

Remember that the top is what puts together the total percent correct. That number (total percent correct) is compared in a vacuum against other folks to form your total percentile rank.

You usually can't average percentiles to reach your clinical percentile. You have to look at the percentage correct. Although I will say that I am confused as to why your total percentile would be lower than ALL of your subsections (including bio/phys).

Look at your percent correct, added up from all your various clinical subsections. If you want to, scan and PM me a copy of your report (blocking the name) and I can look through if you'd like.

 

[Chartreuse Wombat]

Simpson's Paradox?
Simpson's paradox - Wikipedia

 

[CaesarRO]

One last question for today. Just trying to figure out where to optimize my time with only a month till the exams. On the 2017 in service, my overall percentile ranking was significantly lower than my percentile on any of the subsections. Does anyone know why this might be? I don't wanna say exsactly what mine were, but say the only three subsections for clinical were 1) H&N (and I get 20th percentile) 2) lung (and I get 60th percentile) and 3) gyn (and I get 50th percentile.). Why would my overall percentile be 10th? Is perhaps the overall percentile against only those in your PGY level, while each subsection is against all the test takers?

Could it be that those who scored lower percentiles in individual sections made it up in others more than you were able to? I can see how the overall percentile might be lower if that were the case

 

[radiaterMike]

^^^ most likely scenario. Especially for PGY2-3 residents who have not treated most/all disease sites.


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[RadOnc2013]

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[RSAOaky]

The overall percentile is based on the total number correct. There are some disease sites on the in-service with 5 questions in them for example. Others have 20. As an example, if a score of less than 50/100 was the 10th percentile, you could conceivably do very well on many 5 question sections and very poorly on a few 20 question sections and be in the 10th percentile.

 

[RadOnc2013]

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[Brim]

The answer is because that's what it is.

Consider the following example where you're Person 0.

And here's a 2nd example where you score the same percentile for Test A, B, and C, but score in the 50th percentile overall.

So, you can see that your overall percentile rank depends not just on your individual scores but on the individual performances of the others in the comparison group.
There's nothing anomalous about your ranking.

 

[RadOnc2013]

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