关键词: 人口流动, 生育水平, 选择性, 倾向得分匹配

Abstract: With the counter-factual causal inference framework，this paper employs various propensity score matching methods to explore the effect of selectivity of migration on the fertility level of floating population in China，and estimates and compares migrant and non-migrant fertility levels after controlling for the selectivity bias. Both lifetime fertility( children ever born) and period fertility( births in the year proceeding the census) are examined using data from the 2000 census. Heckman 2-stage model shows that the observed difference between migrant and non-migrant fertility is biased due to selectivity of migration. The consistent results from three types of propensity score matching methods demonstrate that migrant fertility is markedly lower than non-migrant fertility，and a larger proportion of the difference is explained by the selectivity. Anyway，the study suggests that migration does reduce fertility.

Keywords: Migration, Floating Population, Fertility Level, Selectivity, Propensity Score Matching