Alex Tabarrok points to a Duke University working paper that tracks the performance of students through the university and attempts to measure the educational impact of affirmative action programs. As you can imagine the paper is controversial.
So the basic story is that a cohort of students is accepted to university with varying entry scores. These students get to nominate a major and then their progress is recorded over time until graduation. You’d think universities would routinely evaluate this sort of information. Alas, no. Anyway, what happened in this instance? The grade differential between black and white students declines over time. So far so good. But that is explained by black students choosing easier majors – in particular by switching majors from harder to easier subjects. (Read from majors that involve maths to those that don’t).
In fact, black/white gpa convergence is symptomatic of dramatic shifts by blacks from initial interest in the natural sciences, engineering, and economics to 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.
But Tabarrok tells us …
An important finding is that the shift in major appear to be driven almost entirely by incoming SAT scores and the strength of the student’s high school curriculum. In other words, blacks and whites with similar academic backgrounds shift away from science, engineering and economics and towards the easier courses at similar rates.
So all students with lower incoming scores are more likely to change from harder to easier majors but black students are more likely to have lower initial scores. This does suggest that universities (or at least Duke) are not very good at catch-up programs for educationally disadvantaged students (now we can argue over why that is the case – there is enough blame to go around). The other point, however, is that most students (included in the study) graduate. So if it turns out that you’re no good at designing bridges you can become a sociologist. Graduation is not a trivial event in any discipline. So the US model has the benefit that students can drop out of majors, but that doesn’t necessarily mean dropping out of university.
The ideal follow up study would be to compare students with low initial scores that go to university (even if they change majors) with those who do not. I suspect we’d find that the university experience added value irrespective of whether the student majored in a hard or easy subject. The early evidence is in; graduates tend to earn more than non-graduates who earn more than high-school leavers who earn more than high-school drop-outs. So the Duke affirmative action program might not produce black engineers but it is producing black graduates.
Back to the study; I suspect this is a story about maths education. Maths is important especially in the early years. Unfortunately doing maths is boring – for example, times tables must be learned by rote and repetition – and few kids want to do it and qualified teachers are scarce.