What is the true gender wage gap? A comparative analysis using data from Poland

Given the proliferation of methods to estimate gender wage gap, practical issues arise. The aim of this paper is to compare estimates of the adjusted wage gap from different methods and sets of conditioning variables. We apply available parametric and non-parametric methods to LFS data from Poland for 2012. While the raw gap amounts to nearly 10% of the female wage, after the correction for the endowments, the adjusted wage gap estimates range between 15% and as much as 25% depending on the method and the choice of conditional variables. The differences across methods and conditioning variables do not exceed 3pp. The largest differences emerged between methods estimating gap at the mean and those operating at quantiles. Within the same moment, methods which account for selection into employment yielded higher estimates of the adjusted wage gap. When expanding the conditioning set, to account for possible sorting of women into lower paid jobs, estimates of gap increase. While the actual point estimators of adjusted wage gap are slightly different, all of them are roughly twice as high as the raw gap, which corroborates the policy relevance of this methodological study.