性别工资差异的动态演进及形成机制：来自公司人事数据的实证研究

Women have long been in a disadvantaged position in the labor market. Since the Reform and Opening Policy, Chinese women’s education is catching up and even surpassing that of men. However, the gender wage gap is widening instead. Understanding the determinants of gender wage difference is crucial for designing income distribution policies and protecting women’s rights. A majority of previous research about the gender wage gap in China used household surveys and decomposed the gender wage difference into the “explained component,” which can be accounted by the observable human capital, and the remaining “unexplained component”, which is often interpreted as “gender discrimination.” Simply attributing unobservable factors in a typical household survey to “gender discrimination” restricts our further understanding of the gender wage difference. This project plans to use a new administrative data from a large listed company to complement current research on gender wage difference. First, this project documents the dynamics of gender wage difference since the employee’s entrance into the firm. Second, this project further investigates three possible mechanisms underlying the gender difference, including: marriage and childbearing, labor productivity, and gender discrimination. Finally, this project exploits changes in China’s family planning policy (selective two-child policy and universal two-child policy) as exogenous shocks to identify the mechanisms.

女性在劳动力市场上长期处于弱势。自改革开放以来，我国女性在教育水平上不断接近甚至超过男性，但性别工资差距不但没有缩小，反而进一步扩大。理解性别工资差异形成的深层次原因对于制定收入分配政策与妇女权益保护政策都有着重要意义。先前我国相关的研究主要采用家庭入户调查数据，将性别工资差异分解为可以由人力资本差异所解释的“被解释部分”以及剩余的“未解释部分”，“未解释部分”往往被解读为“性别歧视”。该方法将数据中没有观测的信息简单归因于“性别歧视”，这会限制我们对于性别工资差异的深入理解。本项目拟采用国内某大型上市公司的内部人事数据对现有研究进行补充。首先，本项目分析男女员工在进入公司后工资轨迹的动态差异。然后，我们将深入考察性别工资差异的形成机制。我们重点关注三种机制：婚育、劳动生产率、与公司性别歧视。最后，我们拟结合单独二孩政策、全面二孩政策作为外生冲击，以识别上述机制的因果影响。

本项目采用国内某大型上市公司的内部人事数据，对目前普遍采用家庭入户调查的性别工资差异研究进行补充。具体的，人事数据具有三大优势：测度精准、高频、有详细的工作记录。利用该数据，我们分析了男女员工在进入公司后工资轨迹的动态差异，并重点考察了婚育对性别工资差异的影响。我们发现，当年轻员工刚进入公司时并不存在明显的性别工资差异，但到了30岁左右，性别工资差异开始出现并迅速扩大。通过事件研究法，我们发现性别工资差异在员工结婚后开始出现，在生育时到达暂时的高点，尽管产假结束后差异回落到怀孕前的水平，但此后性别工资差异会持续扩大。通过利用详细的工作信息（包括职级、部门、绩效考核、病事假等），我们探索了这种动态变化的形成机制，工作时间的减少解释了生育时点附近短期内的差异顶峰，但长期差异的持续扩大主要是因为女性晋升速度在生育后低于男性导致的。