What can a school’s infrastructure tell us about the quality of its education?

Brazil’s National High School Exam (Enem) was created in 1998 as a way to test the quality of high school education. It has since been turned into Brazil’s main college acceptance exam, and is used by most of the country’s federal universities.

Unsurprisingly, Enem scores reflect deep divisions of class, race, and gender within Brazilian society. Over 70 percent of the exam’s best scores belong to males whose parents have at least a college education. Of course, while it may not be news that a student’s social and economic background plays a large role in educational performance, it would be worthwhile to take a look at just how pervasive inequality is within our school system, and how these imbalances translate into very real and problematic material circumstances.

In this article, I will examine the relationship between the physical conditions of school facilities and the performance of high school students who took the Enem. To give you an idea as to the structural problems we’ll be looking at, consider a few facts: roughly 50 percent of Brazilian schools don’t have access to a sewage system; 5 percent don’t have electricity; 25 percent don’t even have trash pickup.

Students from schools with trash pickup score, on average, 39 more points on the Enem than those from schools without one (Enem scores range from 0 to nearly 1,000). Having access to a sewage system statistically adds 30 extra points to a student’s score. Add...