Comment: 12 pages, 2 figuresDue to the specificity of China's dualistic household registration system and the differences in the rights and interests attached to it, household registration is prevalent as a control variable in the empirical evidence. In the context of family planning policies, this paper proposes to use family size and number of children as instrumental variables for household registration, and discusses qualitatively and statistically verifies their relevance and exogeneity, while empirically analyzing the impact of the household registration system on citizenship of the mobile population. After controlling for city, individual control variables and fixed effects, the following conclusions are drawn: family size and number of children pass the over-identification test when used as instrumental variables for household registration
non-agricultural households have about 20.2% lower settlement intentions and 7.28% lower employment levels in inflow cities than agricultural households
the mechanism of the effect of the nature of household registration on employment still holds for the non-mobile population group.