The Motherhood Wage Penalty Revisited: Experience, Heterogeneity, Work Effort, and Work-Schedule Flexibility
利用1968-88年全美青年女性纵向调查数据，发现人力资本和未观测异质性解释了母亲与非母亲工资差距的55-57%，且中等技能母亲（高中毕业）遭受更持久严重的工资损失，质疑了工作努力解释，转而支持时间约束解释。
This paper seeks an explanation for the well-documented wage disadvantage of mothers compared to women without children. An analysis of data from the 1968–88 National Longitudinal Survey of Young Women shows that human capital inputs and unobserved heterogeneity explain 55–57% of the gap. Further analysis suggests that mothers tended to face the highest wage penalty when they first returned to work. A finding that medium-skill mothers (high school graduates) suffered more prolonged and severe wage losses than either low- or high-skill mothers casts doubt on the work-effort explanation for the wage gap, according to which women reduce work effort in response to childcare duties. The authors instead cite variable time constraints: high school graduates are likely to hold jobs requiring their presence during regular office hours, and are unlikely to gain flexibility by finding work at other hours or by taking work home in the evening.