Quantify Vaccination Versus Confounding in Inflation-Adjusted Estimates of UIP Effects

Determine the relative contributions of true causal effects of infant exposure to India’s Universal Immunization Programme (UIP) versus confounding from inflation, nominal economic growth, and non-random National Sample Survey interview sequencing to the inflation-adjusted regression estimates of the effects on adult log wages and log per-capita household expenditure for cohorts born 1985–1990 in the 2011–2012 National Sample Survey under the identification approach of Summan, Nandi, and Bloom (2023).

Background

The comment critiques Summan, Nandi, and Bloom (2023), who report that exposure to India’s Universal Immunization Programme (UIP) in infancy increased adult wages and per-capita household consumption. The comment argues that the identifying variation in their design arises primarily from survey timing during the 2011–2012 follow-up rather than from the staggered rollout of the UIP.

After adjusting outcomes for inflation, the comment finds that the estimated wage effect persists while the consumption effect largely disappears, raising the possibility that remaining effects may still be influenced by non-UIP factors such as nominal economic growth and non-random sequencing of interviews. The author explicitly states uncertainty about the extent to which the inflation-adjusted results reflect genuine vaccination effects versus these confounders, motivating the need to quantify their relative contributions.