Student Mobility Dropped in New Orleans, But Why?
I've noticed that one topic in school reform debates gets much less attention than it deserves: student mobility.
This is a key metric because it reflects both the hopes and the fears of proponents of choice and market-based reforms. On the one hand, choice supporters argue that these policies allows families to vote with their feet and place pressure on schools to improve. Student mobility allows us to test this theory and better understand what families are looking for and how the market works. It is not only the overall rate of mobility that matters but whether families are moving toward "better" schools. Also, if the system is working, we would expect to see a declining rate of mobility over time as schools respond and do a better job.
On the other hand, prior research suggests that student mobility is harmful to students, at least in the short run. If choice leads to more mobility as families shop around, it could make schooling environments more chaotic and disruptive.
Spiro Maroulis, Robert Santillano, Huriya Jabbar, and I just released a report on mobility through the Education Research Alliance for New Orleans. This is an interesting city to study mobility because attendance zones were eliminated and there are not default schools. Families can and must choose.
Analysis of mobility is complicated, however, by the fact that there are many different types. For understanding school choice, we are mainly interested in students switching schools when they did not have to (what we call "non-structural" mobility). In contrast, students sometimes have to switch schools simply because they finished the last grade available in their current school or because the school closed down ("structural mobility"), which is less informative.
Our first main finding is that non-structural mobility, the type most informative about school choice, declined after the reforms, from 16 to 12 percent. This is highlighted in the figure below:
This was a real shock to some. In fact, one reporter familiar with New Orleans commented, "Wow. Talk about contrary to expectations."
We've already received a lot of questions about the study. The most common request has been for us to explain WHY mobility dropped. But that is actually quite difficult to do. We discuss the various interpretations in the report.
The results are generally consistent with the idea that the market is working to increase the quality of schools that students experience. We isolated the role of characteristics of the initial school ("push" factors) from the characteristics of receiving schools ("pull" factors). Our results suggest that students are more likely to leave schools with low performance scores based on standardized tests (although the pull of high performance is less pronounced). Also, it appears that non-structural mobility declined over time, as the theory predicts.
But we also saw a continuation of a pattern we have seen in essentially every study we've done: the results suggest that the system is not working quite as well for disadvantaged students, in this case racial minorities and those with low incomes. This is highlighted below with steeper declines in mobility for more advantaged groups.
Similarly, we found that low-performing students are inclined to exit low-performing schools but do not tend to move to higher-performing schools. High-performing students, by contrast, tend to leave low-performing schools and move toward better ones.
Because we do not know why mobility declined it is difficult to be sure that these patterns by race and income reflect inequities. But it is more of a concern when we look at the bigger picture of our other studies. For example, Matt Larsen and I found that disadvantaged students experienced smaller increases in test scores and Huriya Jabbar found signs of schools cream-skimming students (at least in the pre-centralized enrollment period captured in this analysis).
As I have pointed out many times before, the results still suggest that disadvantaged students are better off academically under the new system, though the results collectively suggest that they may be falling behind within the district.
But the larger point is that school districts, especially those pursuing charter and choice strategies, should be paying closer attention to mobility rates and patterns to learn how well their systems are working. When families can vote with their feet we need to see where their feet take them, and hope that it does not produce a counter-productive stampede.
Douglas N. Harris is Professor of Economics, the Schleider Foundation Chair in Public Education, and the founding Director of the Education Research Alliance for New Orleans at Tulane University. You can follow him on Twitter