劳动合同对农民工收入的影响机制研究——基于内生转换回归模型的实证分析

Research on the Influence Mechanism of Labor Contracts on Migrant's Income:An Empirical Analysis Based on Endogenous Switching Regression Model

是否签订劳动合同,不仅是法律意识问题,也是经济决策问题。现有研究往往忽略工资决定中的不可观测因素和选择性偏误,导致错误估计工资方程以及劳动合同的异质性边际回报,也无法深入探讨劳动合同对工资收入的影响途径。本文利用修正选择性偏误的内生转换回归模型,同时估计农民工的工资方程和劳动合同的选择方程。研究发现,仅在签订劳动合同组,教育水平、技能和法律意识才能提高农民工工资收入,劳动合同能够降低性别歧视;年轻、城市户籍、有技能证书和法律知识的农民工更倾向于选择签订劳动合同。签订劳动合同的边际回报存在很强的异质性,它是一条向下倾斜的曲线,最大为0.152,最小为-0.072。平均来看,农民工签订劳动合同能够增加3.78%的工资收入。

Taking the heterogeneous marginal returns into account, this article applies endogenous switching regression model to correct selection bias and looks into the mechanism of which labor contract affects the migrants＇ wage. We find that signing labor contracts does not necessarily increase migrants＇ wage income. Only those who signed labor contracts will benefit from education, labor skills and law knowledge. What＇s more, labor contract is helpful to eliminate sex discrimination, and it is a cost-benefit analysis process to sign contract. The migrants of young, with urban register, training certificates and law knowledge are more likely to sign labor contracts. Besides, substantial heterogeneity is found among individual marginal returns of labor contracts signing. The marginal returns vary and the curve of MTE is downward sloping. In average, signing labor contract can bring 3. 78% in crease in income.