Do SAT Scores Really Predict Success?

July 1 -- School's getting out, but the dreaded Scholastic Assessment Test, better known as the SAT, looms just a summer away for next year's high school seniors.

Given this, many might be inclined to agree with the president of the University of California, who announced several months ago that he would like to abolish the test as a requirement for admission to the school. (He would retain the SAT II, which measures achievement within particular disciplines.)

The announcement of his intention sparked an ongoing controversy.

The issue is complicated, and any full discussion should address the issue of the change in scores over the years. (I wish I had a dollar for every baby boomer I've heard say that the scores started to decline just after they graduated from high school).

Other important issues are the renorming of the test, culturally biased questions, ethnic and gender differences in the scores, self-selection of test-takers, differential participation of various sub-groups, the importance of calculators, test preparation, etc.

Artificially Low Correlation?

The big question, however, is: How predictive of success in college are SAT scores? More precisely, what is the correlation between high school SAT scores and first-year college grade point average? (The appropriateness of GPA as a measure of success is also open to question. Grades, for example, often depend critically on the courses taken.)

Most studies find that the correlation between SAT scores and first-year college grades is not overwhelming, and that only 10 percent to 20 percent of the variation in first-year GPA is explained by SAT scores.

This association appears weaker than it is, however, for an interesting, but seldom noted statistical reason: Colleges usually accept students from a fairly narrow swath of the SAT spectrum.

The SAT scores of students at elite schools, say, are considerably higher, on average, than those of students at community colleges, yet both sets of students probably have similar college grade distributions at their respective institutions.