Brookings Study Ties Exclusionary Zoning to Gaps in School Performance

Last week the Brookings Institute released a study by Jonathan Rothwell on the relationship between exclusionary zoning and school performance. He points out that this is the first study linking zoning to educational outcomes. The findings demonstrate that cities with stronger exclusionary zoning policies have larger differences in test scores across schools. This finding makes sense, as exclusionary zoning policies segregate households by income, and household income is strongly correlated with children’s educational outcomes.

This research is important because school district quality is a key factor in families’ decisions of where to live. I think that school quality is likely an important factor behind many NIMBY efforts too, as parents in a neighborhood may be afraid that lower-income residents moving into the school boundary will bring down the quality of education. Whether or not this is a valid concern on NIMBYs’ part, perception is all that matters.

Rothwell’s dependent variable is called the school-test score gap, or the difference between a school’s test results and the state’s test results. So his results don’t tell us whether reducing exclusionary zoning will improve individuals’ outcomes or merely bring schools’ averages more in line. Of course what we would like to see is improved absolute educational outcomes, particularly for those students with the poorest performace. Theory does suggest some reasons that more equal schools could improve absolute student results, one being that more experienced teachers typically do not work in a city’s worst-performing schools. Another is that students may do better when they are surrounded by higher-achieving classmates. Through those channel and perhaps others, reducing disparities across schools could improve low-income students’ results.

In developing the case for why it’s important for children of all income levels to attend schools with higher median test scores, Rothwell cites studies that demonstrate that “the quality of schooling is enormously important to both test scores and future economic success.” However, he also acknowledges that studies involving school lotteries, in which children are randomly assigned to higher or lower performing schools, have less clear results about the impact of schooling on education. This is a key distinction because many studies of education are plagued by the difficulty of collecting data on some of the variables that affect student success. For example, parental involvement in schooling, parents’ time spent reading with children in early childhood, and other aspects of a child’s lifestyle are difficult and expensive to measure. Understandably, then, these variables are often omitted from studies of educational outcomes, biasing the estimated impacts of the variables researchers do include. This is particularly true when studying the effects of a child going to a higher-performing school without a lottery; a parent who makes a significant effort to get his child into what he believe is a better school than the neighborhood school is likely making extra effort to help out his child’s education at home in other ways.

While Rothwell is supportive of policies such as charter schools and voucher programs that give parents the opportunity to send their children to schools outside of the one tied to their address, he seems to be even more supportive of eliminating exclusionary zoning and requiring municipalities to allow multifamily housing. While clearly I am against exclusionary zoning, I’m not convinced that this is necessarily the right policy tool for improving educational outcomes. Instead, I would suggest any policies that move away from requiring children to go to the school in their neighborhood. This connection eliminates any semblance of competition among schools and contributes to the incentives for residents to lobby against potential new neighbors. Land and education are two separate markets that government has tied together with negative (un)intended consequences.

From an educational perspective, though, one reason to support the elimination or reduction of exclusionary zoning is that this would allow more people to move to cities. Cities contribute to economic growth, and we know that children from higher income families tend to do better in school. Future studies could build on what Rothwell has contributed by looking at low-income students’ educational attainments when land use restrictions are relaxed or when school attendance is not tied to where they live.

Note: Rothwell also recently wrote a great piece in The New Republic about zoning as an extractive institution. I hope to write more about zoning from a new institutional perspective in the near future.