The heterogeneous impact of parental leave take up on the wage distribution: Evidence from Luxembourg

We analyze the causal effects of taking parental leave on the post-birth hourly wage distribution of parental-leave-eligible mothers in Luxembourg. To deal with selection into parental leave, we match participants with non participants’ rich pre-intervention characteristics obtained from Social Security records for 2005–2010. In addition, we deal with selection into employment by using principal stratification and non parametric bounds. While the key identifying assumptions employed are not refutable (e.g., unconfoundedness and monotonicity), we present suggestive evidence about their plausibility in our context. Inference is for a subpopulation of parental-leave-eligible mothers who are always employed regardless of parental leave participation—about 80% of all eligible mothers. Our estimated bounds on quantile treatment effects of parental leave suggest substantial negative and significant impacts in most quantiles above the median of the wage distribution. These wage penalties, which are bounded between 10 and 26%, appeared present for high-earner mothers 2–5 years after parental leave.本研究针对卢森堡境内符合育儿假（parental leave）申请资格的母亲，分析其休育儿假对产后小时工资分布（hourly wage distribution）的因果效应。为解决育儿假参与过程中的选择性偏差问题，我们基于2005至2010年的社会保障记录（Social Security records），将育儿假参与者与非参与者的丰富干预前特征进行匹配。此外，我们通过主分层（principal stratification）与非参数界（non parametric bounds）处理就业选择偏差。尽管所采用的核心识别假设（identifying assumptions）无法被证伪（如无混淆性unconfoundedness与单调性monotonicity），但我们仍提供了该类假设在本研究场景下合理性的提示性证据。本研究的统计推断针对一类子群（subpopulation）：即无论是否参与育儿假均始终就业的符合资格母亲，这类群体约占所有合格母亲的80%。我们对育儿假分位数处理效应（quantile treatment effects）估计得到的界值显示，在工资分布中位数以上的多数分位点上，育儿假存在显著的负向影响。这类介于10%至26%之间的工资惩罚（wage penalties），在育儿假结束后2至5年的高收入母亲群体中显著存在。