Basic Statistical Mistakes

June 24, 2011 No Comments

I’m reading ‘In the Basement of the Ivory Tower’ by the pseudonymous ‘Professor X,’ who teaches English 101 and 102 as an adjunct at two unnamed colleges in the North East – one a small liberal arts college and the other a community college. Professor X’s point is that colleges are over admitting under prepared students, and relying on the temporary adjunct staff to do the dirty work of failing the unprepared out of the program.

This is not a particularly radical claim. But it is worth pointing out a bit of the reasoning:

The increased use of adjunct instructors is a direct result of the explosion in college enrollments, which have expanded dramatically since 1980.  In 1940, there were 1.5 million college students in the United States.  Twenty years later the figure had doubled, to 2.9 million. In 1980, there were more than 12 million students enrolled in college, and by 2004, we were up to 17.5 million. Census projections for 2016 hover around 21 million. Everybody goes to college now, though not everybody graduates.

Sounds terrible, doesn’t it?

Why, however, does ‘Professor X’ give these numbers as quantities, rather than relative to the population of the US – which grew a great deal between 1940 and 2016.  Isn’t that just obvious?  Here’s the numbers in relation to the population:



Year College Students (in millions) Population of US (in millions) Percentage
1940 1.5 132 0.01
1960 2.9 139 0.02
1980 12 228 0.05
2004 17.5 293 0.06
2016 21 329 0.06

And here’s the chart:

So it turns out that the big rises in college enrollments as a function of the population happened between 1940 and 1980 – this is no surprise, as the GI Bill famously revolutionized the state university during this period. The change between 1980 and 2016 is less than 1 percent of the population. I can think of no other industry that would be comfortable with this kind of growth relative to the growing population. Surely, then, the rise in number of students cannot be blamed for the rise in adjunct population, which Professor X dates to the 1980’s and 1990’s.

Professor X ends the paragraph by asserting that ‘Everyone goes to college now.’ That is clearly false, even without considering college population to the overall population.  It is so false that it even seems laughable. So what is it doing here?

I would contend that Professor X is inserting an exasperated exaggeration for rhetorical effect. He (and it is clear from the book that Professor X is male) doesn’t literally mean that everyone goes to college. But he’s lamenting that there are people going to college who don’t deserve it. The toss-away phrase becomes a shibboleth – a way for him to identify himself as a fellow elitist to like-minded readers. It thus becomes a kind of appeal to character.

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Tags: , , Analysis, Appeals to Character (Ethos), Featured, Statistical reasoning

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