Survey-based research finds sizeable unexplained wage gap between mothers and nonmothers in affluent countries.
The study published by demographic-research.org in December 2017 set out to “open the black box of the motherhood wage gap by directly measuring discrimination in Switzerland based on two complementary methods.
Authors Daniel Oesch, Oliver Lipps, and Patrick McDonald used two longitudinal population surveys to establish the size of the wage residual for motherhood. They then ran a factorial survey experiment among HR managers (N=724) whom we asked to assign a starting wage to the resumes of fictitious job candidates.
The results of the study suggest an unexplained wage penalty per child of 4% to 8%. Researchers explained the factorial survey experiment shows that recruiters assign wages to mothers that are 2% to 3% below those nonmothers.
Furthermore, the study suggests the wage penalty is larger for younger mothers, 6% for ages 40 and younger, but disappears for older mothers or mothers in a blue-collar occupation.
Research authors concluded the motherhood wage gap found in panel studies cannot be reduced to unobserved dimensions of work productivity. They explained the experimental evidence shows that recruiters discriminate against mothers.
The study notes this approach could also stem from unobserved effects of motherhood on productivity.