“What Happens After Enrollment? An Analysis of the Time Path of Racial Differences in GPA and Major Choice”, Peter Arcidiacono, Esteban M. Aucejo, Ken Spenner2012-10-09 (; backlinks)⁠:

At the private university we analyze, the gap between white and black grade point averages falls by half between the students’ freshman and senior year. This outcome could suggest that affirmative action policies are playing a key role to reduce racial differences.

However, this convergence masks two effects:

  1. the variance of grades given falls across time. [selective attrition/selection bias + restriction of range]

    Hence, shrinkage in the level of the gap may not imply shrinkage in the class rank gap.

  2. grading standards differ across courses in different majors.

We show that controlling for these two features virtually eliminates any convergence of black/white grades. In fact, black/white GPA convergence is symptomatic of dramatic shifts by blacks from initial interest in the natural sciences, engineering, and economics to [easier] majors in the humanities and social sciences.

We show that natural science, engineering, and economics courses are more difficult, associated with higher study times, and have harsher grading standards; all of which translate into students with weaker academic backgrounds being less likely to choose these majors. Indeed, we show that accounting for academic background can fully account for average differences in switching behavior between blacks and whites.

…In particular, natural science, engineering, and economics classes have average grades that are 8% lower than the average grades in humanities and social science classes. Note that these averages do not take into account selection into courses: average SAT scores of natural science, engineering, and economic majors are over 50 points higher than their humanities and social science counterparts. Although blacks and whites initially have similar interests regarding whether to major in the more strictly graded fields, the patterns of switching result in 68% of blacks choosing humanities and social science majors compared to less than 55% of whitesd. We show that accounting for these two issues can explain virtually all the convergence of black white grades.

Accounting for shrinking grade variances and course selection also explains the convergence in grades for a group where we would expect catch up to not occur: legacies. Legacies at Duke start out behind their white non-legacy counterparts (though not as far back as blacks) with 65% of the gap removed by the end of the senior year. Similar major-switching patterns occur for legacies as well, with large shifts away from the natural sciences, engineering, and economics towards humanities and social sciences. The different grading standards across courses legacies and blacks take, coupled with the tighter variances on the grade distributions of upper year courses, accounts for their catch up to their white non-legacy counterparts.

The convergence of black/white grades is then a symptom of the lack of representation among blacks in the natural sciences, engineering, and economics. Over 54% of black men who express an initial interest in majoring in the natural sciences, engineering, or economics switch to the humanities or social sciences compared to less than 8% of white men. While the similar numbers for females are less dramatic across races, they are nonetheless large: 33% of white women switch out of the natural sciences, engineering, and economics with 51% of black women switching.

…Table 8 restricts the sample to those students who reported an expected major. This table shows that blacks are much less likely than their white counterparts to persist in natural science, engineering, and economics majors. While overall the proportion of blacks expressing an initial interest in natural science, engineering, and economics major is almost 1 percentage point higher than the proportion of whites, the final proportion graduation on these fields of studies is over 20 percentage points lower. Among whites, the proportion that start out in natural science, engineering, or economics is 10 percentage points lower than the proportion who finish in these majors, but this is substantially smaller than the rate for blacks. Differences conditional on gender are also stark. Both black males and black females express higher initial interest in natural science, engineering, and economics majors than their white counterparts, yet both show substantially lower proportions choosing natural science, engineering, or economics as final majors. If we condition on the subsample that report an initial major, 76.7% of black males initially choose natural science, engineering, or economics majors but only 35% obtain a degree in one of these majors. For black women, the numbers are less extreme but nonetheless stark: 56% start in economics, engineering, or natural science majors, though only 27.7% has graduated in one of them. In contrast, the differences between initial and finishing proportions in natural science, engineering, and economics are 5 percentage points and 17 percentage points for white males and white females respectively.

See Also: