Co-Principal Investigators: Backes,Ben; Goldhaber, Dan

Purpose: Researchers will investigate the effects of departmentalized instruction in primary schools with a focus on assessing implementation in routine settings and the contributions of specific causal mechanisms. Researchers will study whether the effects of departmentalization on student outcomes change with the number of years of implementation. Researchers will explore the extent of teacher specialization in the years following the policy change. This analysis will both provide evidence on the implementation and effects of these policies and provide an opportunity to assess the external validity of recent experimental evaluations. Primary research questions include:

1. What are the short-run effects of DI on student achievement, attendance, school climate, and grade promotion?
2. How do the effects of DI vary by the number of years it has been implemented at a given school?
3. What are the long-run effects of DI on students' academic achievement in middle school?
4. How do schools implement DI and change hiring and staffing practices?
5. Are the returns to teaching experience different in specialized classrooms?

Project Activities: The study consists of quantitative and qualitative data collection in Massachusetts. The research team will conduct an empirical study of the effects of DI using administrative data on elementary school classrooms. In addition, the study will incorporate qualitative data from surveys of principals, teachers, and students and structured interviews with school principals.

Products: The research team will produce two research papers and a policy brief synthesizing the evidence on the efficacy and cost of implementing DI in elementary school classrooms. Researchers will also conduct a cost analysis focusing on changes in staffing costs that is informed by the interviews with school principals.

Structured Abstract

Setting: This project will take place in Massachusetts, which has the 17th largest public school system in the country and currently has about 1 million students and 70,000 teachers in its public schools.

Sample: The sample will consist of all primary schools in Massachusetts serving students in grades 3–6 between 2008 and 2019.

Intervention: Grades with separate classes and teachers for math, English language arts, social studies, and science instruction.

Research Design and Methods: Researchers will use a difference-in-differences design at the school, grade, and year level. Researchers will identify departmentalization from schools that partially switch from self-contained to departmentalized classrooms (or vice versa) in a given year, with other grades in the same school and year providing estimates of the counterfactual trend in student outcomes. For the third research question, researchers will use a difference-in-differences design at the school and year level that compares the outcomes of cohorts of students in departmentalized classes to prior cohorts in the same schools that were not departmentalized. Researchers will conduct structured interviews with principals in schools that have recently switched instructional models. The interviews will cover reasons for switching models, the timeline and key preparatory steps for the transition, and changes in hiring and staffing practices.

Control Condition: Grades with self-contained classrooms where a single teacher is responsible for instruction in math, English language arts, social studies, and science.

Key Measures: The key student outcomes are school attendance, standardized test scores in math, English language arts, and science, climate surveys, and access to advanced courses. Teacher outcomes include teacher certification status, subject-matter licensure test scores, and value-added estimates.

Data Analytic Strategy: The primary research design uses linear regression models with school-by-grade, school-by-year, and grade-by-year fixed effects. The analysis for research question 3 uses linear regression models with school-by-grade and grade-by-year fixed effects.

Cost Analysis: The research team will conduct a cost analysis focusing on changes in staffing costs that is informed by the interviews with school principals.