So, I had this same question as I undertook a project for my econometrics class this last semester. I decided to run a heteroskedastic robust ordinary least squares estimator (I also ran a LOGIT model since binary dependent variable) to find the solution to this question. Not to give too much info--if you want more, I'll give it--but I acquired the data from the Health Pro advisement center that they acquired since 1994 for all students from my school applying to med schools (osteo and allo). The dependent variable was a binary variable of acceptance or not (who cares if you got accepted to 10 schools; you can only go to one). Variables included all of the MCAT scores by section (WS given a numerical value), Science GPA, All other, Total GPA, # of schools applied to, and whether you took MCAT in August or April.
Results:
If you divide the OLS estimators by their standard deviations, you get a "standardized coefficient" which is what we want since GPA has a range of 0 to 4 and the MCAT has a range from 1 to 15. So the results are the standardized coefficients. Since our dependent has a range of zero or one, you can assume these coefficients are percentages (i.e. Increase your verbal MCAT score by 1 point and you will increase your probability of being accepted by x amount--be aware that I divided by the standard deviation, so this intuition doesn't necessarily work out; just a help).
**Verbal MCAT=.137
**Physical MCAT=.080
Bio MCAT=.0449
Writing Sample=.0276
*Science GPA=.1943
All other GPA=.0527
Total GPA=.0285
**# Schools applied to=.1333 (duh)
*MCAT April=.0672
MCAT August=.0000
sample N=1564 R squared=.21 (awesome for a binary model!)
** denotes the coefficient is significantly different from 0 at the 1% level
* denotes the coefficient is significantly different from 0 at the 5% level
Interpretation:
Ace your science classes, since it accounts for almost 20% of your admittance according to this model. Study your verbal section of the MCAT. Forget the bio section; it wasn't even significant at the 15% level. The writing sample is even worse, not even at the 25% level. Don't apply to just three schools; you'll regret it. And don't even think about missing the april MCAT.
I hope this puts the debate about WS to rest. Adds a new debate, though, the bio score.
By the way, I got an A.