STUDENT GROUP DIFFERENCES IN PREDICTING COLLEGE GRADES: SEX, LANGUAGE, AND ETHNIC GROUPS
Authors: Ramist Leonard , Lewis Charles , McCamley‐JENKINS Laura 
Published: August 2014

Part 1 of this study investigated possible causes of the observed decline in correlations between SAT scores and freshman grade‐point average (FGPA). The results were described in Chapter 12, “Implications of Using Freshman GPA as the Criterion for the Predictive Validity of the SAT,” and were the basis for much of Chapters 2 and 3 of the monograph Predicting College Grades: An Analysis of Institutional Trends Over Two Decades (Willingham, Lewis, Morgan, and Ramist 1990). Working with a data base of 38 colleges, the study found that the comparability of course grades received by entering freshmen declined in the 1980s. Three new measures of grade comparability—variety of courses taken, variation in average student aptitude among courses, and appropriateness of average course grade in relation to student aptitude level—proved to be excellent indicators of both the level of and the change in SAT validity for predicting FGPA among the 38 colleges. Using course grade as the criterion instead of FGPA reduced the decline in both SAT and high school GPA (HSGPA) validity for predicting course grades by 40 percent. Contrary to the assumption that high school record (HSR) is a better predictor than the SAT, compared with HSR the SAT had higher or equal average validities for predicting course grade in almost all categories of courses. (Each course was placed into one of 37 categories based on subject, skills required, and level.)

Part 2 of this project examines course selection, grading patterns, grade comparability, SAT predictive effectiveness, and average over‐ and underpredictions in each type of course for groups defined by an academic composite index, sex, English as best or not best language, and ethnic group. SAT predictive effectiveness is determined with and without HSR on the basis of correlations that are corrected for restriction of range. Over‐ and underpredictions are determined by residuals from predictions. All results are analyzed by college selectivity level and size.

On average, males took more rigorously graded courses and females obtained a higher FGPA: two‐thirds of the .09 difference by sex in FGPA related to course selection. Predictions of course grades based on the SAT were better for females, on average, than for males, and the SAT added more incremental information over HSR for females. Underprediction of FGPA for females, using the SAT and HSR, averaged .06. Underprediction of course grade for females, using the SAT and HSR, averaged .03, but was reduced to .02 using the Test of Standard Written English (TSWE) as an additional predictor, and was eliminated entirely at more selective colleges.

Although on average the SAT predicted FGPA and course grades better for students whose best language was English, it added more incremental information over HSR for students whose best language was not English. Asian American students took, on average, very strictly graded courses, but obtained a high average FGPA. The SAT predicted FGPA and course grades better for them than for any other ethnic group. On average, the SAT added more incremental information over HSR in predicting FGPA and course grades for black students than for any other ethnic group. Course grades were the least comparable for Hispanic and black students. They were so lacking in comparability for Hispanic students that, on average, there was better prediction of one course grade, as long as the course was identified, than of FGPA, even though the latter was typically based on eight or nine courses (for black students, course grade and FGPA predictions were equally good).

On average, substantial improvement in the prediction of FGPA could be obtained by using, as an additional predictor, the average grading difficulty of courses selected by students. The improvement was greatest at less selective colleges and for students of lower academic levels.

The highest average correlations in predicting FGPA were obtained by predicting each of a student's course grades separately and averaging the predictions to obtain a predicted FGPA. After correcting for predictor restriction of range and criterion unreliability, the average correlations were .64 for the SAT, .67 for HSR, and .75 for the multiple correlation of the SAT and HSR. These correlations may be the best estimates ever made of the effectiveness of the SAT and HSR for predicting FGPA, because they were based on a large cross section of colleges and on comparable grades for all courses taken by a student, and because the effects of both predictor restriction of range and criterion unreliability were removed.