Month of birth and child height in 40 countries

- Replicates and refutes a recent study on effects of month-of birth on child health.
- Systematic age differences by month of birth leads to artificial seasonality in HAZ.
- Finds evidence of measurement error in DHS birth month data in 40 countries.

Lokshin and Radyakin (2012) present evidence that month of birth affects child physical growth in India. We replicate these correlations using the same data and demonstrate that they are the result of a spurious relationship between month of birth, age-at-measurement and child growth patterns in developing countries. We repeat the analysis on 39 additional countries and show that there is no evidence of seasonal birth effects in child height-for-age z-score in any country. Furthermore, we demonstrate that the Demographic and Health Survey data used to estimate the correlation is not suitable for the task due to a previously unrecognized source of measurement error in child month of birth. We document results from several papers that should be re-interpreted in light of this issue.