The Effect of the One-Child Policy on Fertility in China: Identification Based on the Differences-in-Differences

This paper measures the effect of China's one-child policy on fertility by exploring the natural experiment that has been created by China's unique affirmative birth control policy, which is possibly the largest social experiment in human history. Because the one-child policy only applied to Han Chinese, but not to ethnic minorities, we construct a differences-in-differences estimator to identify the effect of the policy on fertility. Such a natural experiment is a rare opportunity, whether for the analysis of the effect on fertility or for the analysis of economics in general. Using two rounds of the Chinese Population Census, we find that the one-child policy has had a large effect on fertility. The average effect on the post-treatment cohorts on the probability of having a second child is as large as -11 percentage points. We also find that the magnitude is larger in urban areas and for more educated women. Our robustness tests suggest that our differences-in-differences estimates of the effect of the one-child policy are not very likely to be driven by other policy or socio-economic changes that have affected the Han and the minorities differently.