Disentangling the Role of High School Grades, SAT Scores, and Socioeconomic Status in Predicting College Achievement

• In Event: Students’ Diversity and Test Fairness

Abstract

Thousands of statistical studies have been conducted in which the goal was to predict college GPA using high school GPA and SAT or ACT scores. These studies largely fall into two categories—those conducted by universities to help formulate admissions policies and those performed to investigate the validity of admissions tests. This enormous body of literature has produced one consistent conclusion: High school GPA is a better predictor of college GPA than are admissions test scores. For example, Atkinson and Geiser (2009, p. 666) stated that “it is useful to begin any discussion of standardized admissions tests with acknowledgment that a student’s record in college preparatory courses in high school remains the best indicator of how the student is likely to perform in college.”
But is the widely cited belief that high school grades are better than test scores for predicting college performance a correct one? The answer depends on the evaluation criteria. One way to compare the quality of predictors is in terms of how heavily they are weighted in a regression equation that includes both of them. In these terms, high school GPA is a clear winner. Another criterion that has emerged is more political: Some commentators argue that predictors of college performance should be unassociated with socioeconomic status (SES) to the degree possible. High school GPA is regarded as a superior predictor to test scores because it is said to be relatively untainted by socioeconomic status, an assertion that proves to have only weak empirical support. A third aspect of prediction quality that is often overlooked involves systematic prediction errors that can exist even in the presence of a strong association between the predictor and the predicted quantity. With respect to this criterion, high school GPA generally makes a poor showing.
I will draw on my recent research in addressing these issues: In a study of nearly 100,000 students, Zwick and Green, 2007 showed that, if analyses are conducted within high schools and then pooled, the association between high school grades and SES is only slightly smaller than the association between SAT scores and SES. That is, much of the association is at the school level, rather than the student level. In another large study, Zwick and Himelfarb (in press) compared three regression models for predicting college grades. For some student groups, models with HSGPA only as a predictor had large prediction errors that were reduced substantially by adding SAT scores to the prediction equation. Further reductions were achieved by including a measure of school-level SES as a predictor. I will discuss the fairness implications of these results and related findings by other researchers.
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Educational Researcher, 38, 665–676.
New perspectives on the correlation of SAT scores, high school grades, and socioeconomic factors. Journal of Educational Measurement, 44, 23-45.
The effect of high school socioeconomic status on the predictive validity of SAT scores and high school grade-point average. Journal of Educational Measurement.

Author

• Rebecca Zwick, Educational Testing Service