Society and Culture, Education

SAT Scores Explain Some Graduation Variation—But Not Much

The categories of competitiveness used in “Diplomas and Dropouts” come from Barron’s, which used various factors in their school selectivity ranking, including SAT/ACT scores. However, within each category, there was some variation in SAT scores, and based on very preliminary analysis, it looks like that variation can explain some of the difference in graduation rates within categories, but not much.

Within each of the top three categories of competitiveness—or what Barron’s calls “Very Competitive,” “Highly Competitive,” and “Most Competitive”—the five schools graduating the highest percentage of students had higher average SAT scores than the five schools graduating the lowest percentage of students. For instance, in “Very Competitive” schools, which generally accept between 75 percent and 85 percent of applicants, the top-graduating schools had average verbal SAT scores for the 25th percentile to 75th percentile of incoming freshmen of 522-630, compared with 470-602 for the bottom-graduating schools in that category. Those aren’t massive differences, but they may be meaningful—and there are similar differences in verbal and math scores in each of the top three competitiveness categories between the top- and bottom-graduating schools (I didn’t look at the bottom two, since as schools get less competitive, fewer applicants submit SAT scores, so inter-school comparisons become less helpful).

When we look closer, though, we can see that SAT scores can’t explain the huge differences between top- and bottom-graduating schools within each category. For instance, Fairfield University is the fifth-highest graduator in the “Very Competitive” category. In terms of SAT scores, it looks a lot like Lyon College, which Barron’s characterizes as “Highly Competitive” — that is, even more selective. But Fairfield has an 81 percent six-year graduation rate, whereas Lyon has a 55 percent rate. Maybe there’s something else going on here in terms of SAT scores that isn’t being captured by the 25th percentile to 75th percentile measures: perhaps their bottom quartiles look very different. But more likely, Lyon and Fairfield exhibit different kinds of institutional behavior, or their entering students differ in ways that aren’t captured by SAT scores.

Among the least-competitive schools, which is where graduation rates are the lowest, there’s the least standardized test score data—but we can tell that the huge variations in graduation rates aren’t coming from SAT scores. Southern University at New Orleans, which Barron’s characterizes as “noncompetitive,” meaning it has a largely open admissions policy for high school graduates, graduated only 8 percent of its students. More than two dozen other colleges also reported graduation rates under 20 percent. By contrast, some noncompetitive schools graduated more than half of their students. Presumably, Southern University in New Orleans had its school year severely disrupted by Hurricane Katrina, lowering graduation rates. Also, the two highest-reported graduation rates for noncompetitive colleges—Arkansas Baptist and at 100 percent  and Concordia College at 97 percent—are deep outliers and shouldn’t be taken at face value. Even taking that into account, though, there’s a significant enough range of graduation rates in each category of competitiveness that we can say fairly certainly that the difference between the top and bottom is not purely a product of different SAT scores.

Abigail Haddad is a researcher at the American Enterprise Institute.

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