How to predict a student’s SAT score: Look at the parents’ tax return
This weekend, triggered by a few readers who disagreed with my assertion that socioeconomic status is a huge driver of educational attainment and performance, I decided to respond the way any nerd would in my situation: I made a chart.
In a moment of Excel fervor, I took data from the College Board’s 2011 Total Group Profile Report of college-bound high school seniors and plotted the mean combined (Reading, Math, and Writing) SAT scores for various income cohorts.
Take a look at the chart below. On the horizontal axis is family income. On the vertical axis is the combined average SAT score for students from families in each group. The general story is pretty simple: The higher the parents’ income, the higher their kids’ SAT scores.
(And this, sadly, is but one example. For a fuller account of the link between income and education, see the work of Duke’s Helen Ladd.)
UPDATE (2/21, 5:15PM EST):
Thanks for the mega-response to this post. A few things:
1. Let’s all say it together: “Correlation is not necessarily causation.” Just ask XKCD.
2. Several readers have suggested that the real driver here is the parents’ education level rather than their income. Maybe. But without acquiring the underlying data and subjecting it to a more sophisticated analysis, we can’t say for sure. One thing we do know, from Table 11 of the report, is that among households where at least one parent has a graduate degree, the average combined score is 1687 — which is higher than for most income levels but lower than the average score for the highest income households. What’s more, there are three times as many households with graduate degrees as there are households with incomes over $200K, so something else might be afoot.
3. My hypothesis about that something — a guess rather than an assertion — is that the households in the top tier often have two parents with graduate degrees. That is, they’re rich and they’re well-educated and that’s a hard combo to beat. If that turns out to be true, it suggests that one of the most influential, but least remarked upon, social forces in America is assortative mating by education level.