New CK score and NBME correlate

I think the best way to use the NBME test is this:

Average = 500
Standard deviation = 100

(Your score - 500)/100 = x (this is a z score)

In this formula, your score cannot equal 500 (which would be the average on the current exam, obviously).

Example:
NBME score is 690
(690 - 500)/100 = 1.9

The current Step 2CK exam has the follow stats (I think):

Average = 226 (?)
SD = 23

226 + (x)23 = predicted score on USMLE from NBME test

You can then determine what percentile you are in from your z score:

http://www.epatric.com/documentation/statistics/z-score_table.html

Like if x = 1.9,

Your predicted score would be 226 + (1.9)(23) = ~ 269

You would be in about the 97th percentile.

At least for the Step 1 score report, the SEM was +/- 6.

Therefore, the projected score could be assumed to be 269 (263 - 275) given the SEM. This latter range could be thought of as a confidence interval.


Some people claim their Step scores went up, but note that both the mean and standard deviation are different for Step 2CK. So calculation of a z score and usage of the following table will help you know what percentile you achieved!

Just got my score back. For context, I felt horrible while taking the exam, both because I was really tired and because it seemed like the questions were completely coming out of left field. I felt good when I took the NBME practice test about 5 days pre-test day.

NBME form 4: 640 --> 247
Step 2 CK: 247

So, yeah, still accurate for this n=1.

Horribly inaccurate for me, but maybe I didn't take the NBME as serious when I took it (as compared to the real deal). Who knows.

NBME 3: 204 (8 days out)
Step II: 242

It'sElectric said:

Horribly inaccurate for me, but maybe I didn't take the NBME as serious when I took (as compared to the real deal). Who knows.

NBME 3: 204 (8 days out)
Step II: 242

Click to expand...

Haha, I'd love to have your problem with the NBMEs. But from what I read around, it seems NBME 3 underestimates in general.

i think i did NBME form 1, a week before the real thing: 229
step 2 ck: 257

Took NBME form 2 about 1.5 weeks beforehand.

NBME 2= 252
Real= 261

Since I only studied for a little less than 3 weeks I think it did a pretty good job estimating

i took nbme #2 2 weeks before my test after about 3 days of studying - 256
real - 277

hsans23 said:

i took nbme #2 2 weeks before my test after about 3 days of studying - 256
real - 277

Click to expand...

clearly you knew ur stuff congrats!

hey thanks! i am not the type to score like that so was pretty psyched - - that said, on step 1 i remember i did an nbme a week in and got 245 then on the real thing got 246 so really figured the same would happen for step 2 - - i do wonder if anything the nbmes UNDERpredict your real score b/c no way did i improve that much. for what it is worth! i thought step 2 secrets+UW is all you need though i did do UW x2 once during the year - - and i also read step up to medicine and those old pestana vignettes one time - both of which i found super helpful

NBME 1 217 (2months before) NBME 4: 245 (1month), NBME 3: 243 (2weeks), NBME 2: 239 (5days)

Step 2 CK: 262

I thought it was a lot harder than anything I'd ever seen. The passages were longer and I thought it was tougher than the NBME's.

NBME 4: 215 (2 days prior to taking exam)

Step 2 CK: 232

Step 1: 203

2: 530 (224) - taken about 4 weeks out (I think the 2nd or 3rd day of studying)
3: 630 (245) - taken 2 weeks out
4: 800 (>268) - taken 1 week out

Step 2 CK - 264 - for the record I am typically a horrible standardized test taker, so I think the fact that my predicted was higher than my actual is accounted by this fact. I didn't do any for Step 1 (and I suppose it came back to bite me with a score of 215).

Best of luck!

does nbme 3 underestimate