Reexamining the Effect of Clean Water. A Replication Study of Anderson, Charles, and Rees (AEJ: Applied Economics, 2022)

Abstract

We replicate and extend Anderson et al. (2022), who reassessed the effects of early 20th-century
public health interventions on urban mortality found by Cutler and Miller (2005). Their
study, using two-way fixed effects, found significant reductions in infant mortality. We confirm
their main results but address the concerns about treatment effect heterogeneity inherent in
difference-in-differences with multiple time periods by applying the doubly-robust estimator
of Callaway and Sant’Anna (2021). Our reanalysis finds smaller and statistically insignificant
effects, suggesting that prior estimates may overstate the impact of water filtration.