The current study used data from the China Family Panel Studies (CFPS) in 2018. CFPS is a national, large-scale, multidisciplinary social follow-up survey project, which focuses on the economic and non-economic welfare of Chinese residents, as well as economic activities, educational achievements, family relations and family dynamics, population migration, health, and so on. Conducted by the Institute of Social Science Survey (ISSS), CFPS employs computer-aided Survey technology to meet diverse design needs, improve Survey efficiency and ensure data quality. As a major project funded by Peking University and the National Natural Science Foundation of China, CFPS aims to provide a data base for academic research and public policy analysis. Characteristics of 4–7-year-old children in the valid sample of the present study are: the average age of the children is 5.52 years old, the proportion of boys is 53.2%, and girls account for 46.8% of the whole children, 160 4-year-old children (17.1%), 288 5-year-old children (30.8%), 326 6-year-old children (34.9%), 160 7-year-old children (17.1%).
