On the genetic bias of the quarter of birth instrument

Cornelius A Rietveld; Dinand Webbink

doi:10.1016/j.ehb.2016.01.002

On the genetic bias of the quarter of birth instrument

Econ Hum Biol. 2016 May:21:137-46. doi: 10.1016/j.ehb.2016.01.002. Epub 2016 Jan 27.

Authors

Cornelius A Rietveld¹, Dinand Webbink²

Affiliations

¹ Erasmus School of Economics, Erasmus University Rotterdam, Rotterdam, The Netherlands; Erasmus University Rotterdam Institute for Behavior and Biology, Erasmus University Rotterdam, Rotterdam, The Netherlands; Tinbergen Institute, The Netherlands. Electronic address: nrietveld@ese.eur.nl.
² Erasmus School of Economics, Erasmus University Rotterdam, Rotterdam, The Netherlands; Tinbergen Institute, The Netherlands; Institute for the Study of Labor (IZA), Bonn, Germany.

PMID: 26874780
DOI: 10.1016/j.ehb.2016.01.002

Abstract

Many studies in economics use quarter of birth as an instrument for identifying the causal effect of schooling on outcomes such as earnings and health. The key assumption in these studies is that people born in different quarters of the year do not differ systematically in their unobserved abilities. This study uses genetic data from the US Health and Retirement Study to analyze the validity of the quarter of birth instrument. We find some evidence that genetic factors influencing education are not randomly distributed over the year. However, these factors only slightly change the effect of quarter of birth on schooling.

Keywords: Genetic variation; Instrumental variable; Quarter of birth; SNPs.

MeSH terms

Educational Status*
Humans
Income
Polymorphism, Single Nucleotide*
Reproducibility of Results
Sex Distribution
Socioeconomic Factors
Time*