Are temporary migrants escapees of the one-child-per-family population policy: a revisit to the detachment hypothesis.
Using Hubei province as a case study, this paper retests the detachment hypothesis against the three conventional hypotheses regarding migration-fertility linkage (i.e., selectivity, disruption, and adaptation hypotheses) in explaining migrant and non-migrant fertility differentials in China. The analysis of yearly order-specific birth probabilities suggests that temporary migrants exhibit a significantly higher probability of having a second or higher order birth than comparable permanent migrants and non-migrants. This higher fertility among temporary migrants occurs after migration; temporary migrants actually do not differ from non-migrants in fertility before migration. But permanent migrants experience no significant change in their fertility after migration. The results lend a strong support to the detachment hypothesis, which best explains the fertility differentials between migrant and non-migrant populations in contemporary China; the separation of temporary migrants' actual residence from their official one does lead to a greater likelihood among temporary migrants to have unplanned births.