Authors: Pak Hung Lam, Emma Zang, Dieyi Chen, Riyang Liu, and Kai Chen
Abstract: Elevated exposure to ambient fine particulate matter (PM2.5) has been consistently associated with adverse outcomes on children’s test scores.1 However, previous research has often relied on relatively small or less representative samples and faced challenges in accounting for unobserved confounders at the individual level.2 In this cross-sectional study, we aimed to address these limitations by employing a 2-way fixed-effects model with a large administrative data set in North Carolina. This cross-sectional study followed the STROBE reporting guideline and was approved by the Yale institutional review board with waived informed consent because it was a secondary analysis in accordance with 45 CFR § 46. We obtained student-level administrative data from the North Carolina Education Research Data Center, which included all students in grades 3 to 8 who attended public schools in North Carolina from 2001 to 2018. To ensure comparability across grades and years, following a previous study,3 we standardized the test scores in mathematics and reading at the student level as the dependent variable, normalizing the scale to have a mean of 0 and a variance of 1 for each grade-year. More details can be found in Supplement 1. All analyses were performed in R statistical software version 2022.03.0.386 (R Project for Statistical Computing) with packages fixest, splines, and dlnm. A 2-sided P < .05 indicated statistical significance and data analysis was conducted from March to September 2023.
Key Findings
- Our main findings in this cross-sectional study align with a previous study that also applied a 2-way fixed effects model, albeit using test score data at the geographic school district level rather than individual level.
- Our findings are broadly consistent with other previous research.1
