Research

Publications

NEW! “Are separate classrooms inherently unequal? The effect of within-school sorting on the socioeconomic test score gap in Hungary” (joint w/ Z. Hermann and D. Kisfalusi), Economics of Education Review, forthcoming (Dec 2024) 


Working Papers

Classroom Assignment Policies and Implications for Teacher Value-Added Estimation

Value-added measures of teacher quality may be useful tools to help manage the teacher workforce and improve the efficiency of schools. But this requires that they be reliable estimates of teacher effectiveness. Because value-added scores are based on observational data, they may be biased by systematic patterns in the assignments of students to teachers. Whether assignment processes permit unbiased estimation of teacher value-added is a matter of great dispute. In this paper, I loosen the assumption from past research that assignment processes are identical at all schools. I develop a method for measuring the heterogeneity in school-level assignment practices, and I leverage the variation in practices to learn about the magnitude of biases in teacher value-added estimates. I show that about 60% of elementary schools in North Carolina systematically sort students with higher and lower scores on previous year's tests to different classes - a pattern of student “tracking”. About half of these schools also allocate the classes of high and low achievers to the same teachers year after year - a pattern of “matching” teachers to certain students. Biases in value-added estimates are most likely in these matching schools, and least likely in school that are neither tracking or matching. Using data on teachers who move between the two types of schools, I document strong evidence of systematic and substantial biases in value-added measures. Importantly, these biases are negatively correlated with teachers' true effects, so would not be detected by prior estimates of value-added. Overall, I conclude that the quality of value-added assessments is likely to depend on the nature of the student-teacher allocation process used at specific schools or school systems.


Teacher Peers at School: How Do Colleagues Affect Value-Added and Student Assignments? (draft available upon request)

I estimate the effect of peers, defined as teachers at the same school and grade level, on the own effectiveness of teachers, measured by value-added scores. Traditional estimates using leave-out means imply significant and large positive spillovers among teachers. In this paper, however, I exploit a more compelling research design following Mas and Moretti (2009), which approximates the following thought experiment in a regression framework: A low value-added teacher, Teacher B is randomly replaced by a new, high value-added teacher, Teacher C, at a particular school-grade level. How does the value-added of incumbent Teacher A, who worked at the same school-grade the year before, change in response? Among North Carolina elementary school teachers, I find that the replacement of a teacher by a 1 standard deviation (SD) better teacher, incumbent peers' value-added increases by about 0.09 SDs, which is about one third of traditional estimates. Moreover, I uncover large heterogeneities across schools, which shed light on how much of these estimates are due to pure peer effects among teachers versus student sorting. Using the classification of schools developed in Horváth (2015), I find that the results are driven by schools that sort students to teachers, while estimates are low and insignificant in random assignment schools. Looking at changes in observed student characteristics in incumbent teachers' classrooms reveals that assignments in random schools do not change when a colleague is replaced, just as expected. Therefore, the insignificantly small estimates in these schools provide clean estimates of peer effects. In contrast, average prior achievement in incumbent teachers' classrooms significantly decreases in tracking & matching schools, and so in these schools, student sorting may explain the spillovers among teachers.


The Latinx Great Migration and Its Effects on School Segregation (joint with Jamie McCasland, draft available upon request)

By 2020, children of color under 18 outnumbered non-Hispanic white children in the United States (Vespa and Armstrong, 2020). In this paper, we estimate the effect of this historic demographic transition during which the U.S. has seen its Hispanic population almost triple over the last three decades, on US school segregation. Merging data from the Mexican Migration Project, the Mexican census, the EMIF border survey, the U.S. Census, and NCES Common Core Data on schools, and building on Derenoncourt (2022), we use a shift-share instrument that combines 1990-2000 network links between Mexican states and U.S. MSAs with exogenous Mexican state-level out-migration shocks to isolate variation in the percentage change in Hispanic student shares in U.S. schools districts. We find that for each percentage point increase in the Hispanic student share, the multi-group Theil index of school segregation rises by 0.2 or about 0.3 standard deviations. This effect is driven by school districts without a history of court-ordered desegregation plans. We also present evidence consistent with a “white flight” in response to the arrival of Hispanic students. Ongoing work will attempt to unravel the underlying mechanisms, in particular, the role of policies such as court-ordered desegregation plans or school finance reforms in mitigating the negative effects of racial diversification on school segregation.


Teacher Value-Added and Student-Teacher Matching in Hungary (joint w/ Zoltán Hermann)

Hermann, Z. and H. Horvath (2022): "Tanári eredményesség és tanár-diák összepárosítás az általános iskolákban. Empirikus mintázatok három magyarországi tankerület adatai alapján" [Teacher effectiveness and teacher-student matching in elementary schools: Empirical patterns in three Hungarian school districts], Hungarian Economic Review, Vol. 69, pp. 1377-1406. [in Hungarian, special conference volume commemorating Gábor Kézdi], link: http://www.kszemle.hu/tartalom/cikk.php?id=2086


The Effects of Teacher Pay Reforms on Teacher Pay, Teacher Careers and Student Attainment (joint with J. Anders, A. Bryson and B. Nasim, ESRC Grant No. ES/R00367X/1, updated draft coming soon)