# Converting Basic Science shelf to USMLE

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#### tbrown

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I recently took the NBME combined basic science shelf. Is there a way to convert your score to a prospective USMLE I score. Also, does anyone know the national mean and SD for this shelf? I know national mean for most shelf's is 70, but I also heard the mean for the CBSE is in the 60's?

#### fuzzyerin

##### Senior Member
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This is what I got from last year (I'm assuming it's approximately the same).

Passing score on the mock exam was 62, corresponding to a Step 1 passing of 182.

Our class average was 59.7, corresponding to a 175. (Because no one took it seriously - they gave it to us after a bunch of tests and said - "this is fun, isn't it?")

They say after studying you should go up 20-40 points on your "Step" average, which is about right. I hope that helps you figure it all out - do a little math and you'll be able to come up with some numbers.

#### tbrown

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Do you happen to know what the SD is nationally for the CBSE??

#### Stinger86

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When your school gets the CBSE scores back, they'll also get a breakdown of how they correlate to a USMLE score, plus all the statistics. I think all you have to do is ask your dean or whoever about it.

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#### babinski bob

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The breakdown is as follows....

63 = 183 (passing)
70 = 200
80 = 225
90 = 250

Scores are scaled to have a mean of 70, std dev = 8; std error of mean = 3 (basically means 95% of time you'll score from 64 to 76 if your avereage was a 70).

*Don't ask me why the average for this test corresponds to a 200???? Maybe the average has crept up from a 200 to a 215 since the original scale was put out??? Who knows...

As you can see, every 2 points = 5 points for step 1

#### Joel Fleischman

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so is the 2 digit "mock" score supposed to corelate with the three digit USMLE score...

#### dcpark74

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I just talked to someone yesterday about the CBSE.

no real correlation since it is completely not USMLE format. he said no vignettes or anything clinical...just regurgitative basic science info.

#### HiddenTruth

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dcpark74 said:
he said no vignettes or anything clinical...just regurgitative basic science info.
Who did u speak with?
And which test are u referring to? The CBSE definately had some crazy clinical passages

#### Joel Fleischman

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I definitely had some crazy clinical passages....
high on the cytokine content too...
It got my ass in gear though...

#### Long Dong

##### My middle name is Duc.
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Are we all talking about the 200 question test? That thing was mad clinical and ripped me a new A-hole.

#### Joel Fleischman

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yep the 200 q one... I feel violated.

#### Discobolus

##### Dutch-American
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The 200q CBSE I took a few weeks ago was very, very close to every example of a recent Step 1 I've seen. It was definitely not simple regurgitation and was full of clinical vignettes.

#### Long Dong

##### My middle name is Duc.
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The vingettes were hella long, and by the time I got done reading them I forgot what the hell I was looking for. On top of that each question had like 10 answer choices and it took way too long to elminate it down to 2 choices to guess from. I'm in deep doo doo

#### Joel Fleischman

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Long Dong said:
The vingettes were hella long, and by the time I got done reading them I forgot what the hell I was looking for. On top of that each question had like 10 answer choices and it took way too long to elminate it down to 2 choices to guess from. I'm in deep doo doo
yeah I need to go up more like 40 than 20 points on my "step" grade.
So, is 6 weeks enough to repeat the first two years of med school?