Over representation in some places causes under representation in others. That’s math.

In this article, fivethirtyeight.com claims blacks are “underrepresented at universities nationwide” and Mizzou’s racial gap is typical.

The article makes the following two claims that I think are worth more thought.

  1. Blacks are underrepresented in Mizzou’s undergraduate enrollment at 8.2%, while 15% of the state of Missouri’s college age education is black.
  2. Mizzou’s graduation rate among blacks is “significantly — though not dramatically — worse than trend” compared with other schools. Their conclusion:  “Top private colleges, though they enroll fewer black students, do a somewhat better job of helping them graduate.”

Here’s some more thought about #1.

The authors of the article state in regards to schools they looked at:

We excluded historically black universities and colleges (HBCUs), which have much higher black enrollment and skew the overall figures.

Columbia College is seven blocks from Mizzou. Lincoln University is a 34 minute drive from Mizzou.

Black undergraduate enrollment at both schools is higher than the state average 15% of college age population. At Lincoln University, for example, nearly 38% of undergraduates were black (in 2007, source: US Dept of Education).

I estimate that black enrollment for Mizzou, Columbia College and Lincoln University combined is about 12.6%, much closer to the the 15% state benchmark.

What does that tell me? While 538’s authors, I think, are implying that Mizzou’s underrepresented black enrollment may be due to systematic discrimination of some sort, I believe it’s plausible that black college age students are simply choosing other schools and that is what causes a good portion of the racial gap at the schools they looked at.

There’s only so many college age kids to go around.

More thoughts about #2.

The authors state that the schools like Mizzou aren’t doing as good a job of helping their black students graduate as top private schools.

Or, it’s possible that top private colleges are doing nothing more to help. They may simply be more selective in their admissions, only letting in students who are more prepared for the rigors and challenges of colleges.

This is called selection bias. An indicator of this would be in admission test scores. If students at the top private schools have higher scores, that’s a good sign they are simply selecting better students.

Another consideration is that the HBCU’s attract a good portion of the best students, leaving less qualified students for the other universities. Again, there are only so many college students out there. It’s tough to manufacture them.

Key point: The authors should have incorporated the dynamic of HBCUs.

What if we did the same analysis with barber shops? We looked at a few barber shops. We excluded barber shops with primarily black clientele. We found that black clientele is under represented in the shops we looked at. 

That wouldn’t be at all surprising. It’s primarily because they are over represented elsewhere.

3 thoughts on “Over representation in some places causes under representation in others. That’s math.

  1. the closest ive ever been to teaching was a few year stint as instructor at prototype while in the navy. my particular field – nuclear engineering was also ‘underrepresented’ re: blacks. i dont know why that was – the nfqt (nuclear field qualifications test (or something like that)) wasnt all that difficult from what i remember. i can count the number of black skinned nukes i knew in my entire six years on both hands.
    clearly, the fact that there were other naval jobs equally as financially rewarding that didnt seem to have this problem (e.g. cryptotechs) may be same thing causing the observed ethnic skew?

  2. Pingback: Preparation is key #2 | Our Dinner Table


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