Like father like son? Revisiting the role of parental education in estimating returns to education in China

Parental education has been used as an instrument in the earnings equation to deal with the endogeneity problem of education. Recently, however, many have found that parental education can be a proxy for unobservable networking, which directly affects wages. This article revisits the role of parental education in estimating returns to education by introducing the "geographical isolation" theory. For migrant workers who receive an education and move around to work, parental education affects their education but otherwise is unrelated to their wages, which makes parental education a good instrument in the instrumental variable approach. For local residents who stay in the same place during childhood and adulthood, parental education can directly affect their wages, and is better introduced as a proxy variable using the control variable method. This article identifies the heterogeneous effect of parental education on wages for different Chinese cohorts and contributes to the debate between the control variable and instrumental variable methods in returns to education studies. Moreover, the idea of geographic isolation can help in the search for good instrumental variables for migrant workers, which is valuable when studying the large migrant population in developing countries such as Mexico, China, India, Vietnam, and many African countries.