Twin Data vs. Longitudinal Data to Control for Unobserved Variables in Earnings Functions – Which Are the Differences?*
利用瑞典双胞胎的大样本数据，在同一数据中同时采用纵向方法和双胞胎方法来控制未观测特征，比较两者在估计婚姻对男女收入影响时的差异，并探讨三种可能的解释。
Abstract This paper compares two different approaches empirically to control for unobserved characteristics when estimating the effect of marriage on male and female earnings: the longitudinal and the twins approach. The estimates were obtained by exploiting the longitudinal dimension of a large sample of Swedish twins, so that longitudinal and twin‐based estimates could be obtained in the same sample. The two approaches lead to different conclusions both regarding the role of unobserved characteristics in the cross‐sectional earnings–marriage relationship and the effect of marriage on earnings. The paper investigates three potential explanations of this difference.