kitchen table math, the sequel: SAT scores predict grades in individual courses

Wednesday, February 17, 2010

SAT scores predict grades in individual courses

contra FairTest....

Individual Differences in Course Choice Result in Underestimation of the Validity of College Admissions Systems
by Christopher M. Berry1 and Paul R. Sackett2

ABSTRACT—We demonstrate that the validity of SAT scores and high school grade point averages (GPAs) as predictors of academic performance has been underestimated because of previous studies’ reliance on flawed performance indicators (i.e., college GPA) that are contaminated by the effects of individual differences in course choice. We controlled for this contamination by predicting individual course grades, instead of GPAs, in a data set containing more than 5 million college grades for 167,816 students. Percentage of variance accounted for by SAT scores and high school GPAs was 30 to 40% lower when the criteria were freshman and cumulative GPAs than when the criteria were individual course grades. SAT scores and high school GPAs together accounted for between 44 and 62% of the variance in college grades. This study provides new estimates of the criterion-related validity of SAT scores and high school GPAs, and highlights the care that must be taken in choosing appropriate criteria in validity studies.
Psychological Science
Volume 20—Number 7

Thus, to the degree that prediction of grades is a goal of college admissions systems, SAT scores and high school GPA are clearly useful tools for deciding which college applicants will achieve the greatest levels of academic performance.

Inside the same class, the student with higher SAT scores/h.s. grades does better than the student with lower SAT scores/h.s. grades. High school grades were a slightly stronger predictor than SATs.


Independent George said...

What I'm curious about are the performance of High GPA/Low SAT scores, or Low GPA/High SAT scores.

Catherine Johnson said...

Hey - good question!

I don't think that was in the article (though I only skimmed it).

I can email copies to folks. (I don't think it's available online.)

For years, I've been mystified by the fact that researchers kept finding such a small correlation between SAT scores & college grades. I thought the restriction-of-range issue solved it, but apparently there is a correction for restriction-of-range, which results in SAT scores still not predicting college grades all that well. (Correct me if I'm wrong, please.)

It never occurred to me that the studies were treating a B in college calculus as equivalent to a B in .... not-college-calculus...

Which seems obvious now that this study has pointed it out.

ChemProf said...

I'm not sure of the reference, but there was a study a while ago showing that the odds of completing a STEM major rose sharply around a math SAT score of 650 or so. Below that, students tended to opt for other majors.