The estimated effect of ultrasound availability and implementation of the One Child Policy (births 1979–92)
| Dependent variable: child is male | |||||
|---|---|---|---|---|---|
| Enforcement of One Child Policy | Ethnicity | ||||
| Strong (1) | Medium (2) | Weak (3) | Han, Zhuang & Manchu (4) | Smaller ethnic groups (5) | |
| First birth × ultrasound | −0.003 (0.006) | −0.005 (0.005) | −0.006 (0.005) | −0.006 (0.005) | −0.016 (0.013) |
| Second birth × ultrasound | 0.018*** (0.006) | 0.009* (0.005) | −0.000 (0.007) | 0.014*** (0.005) | −0.001 (0.015) |
| Third (or higher order) birth × ultrasound | 0.031*** (0.008) | 0.023*** (0.007) | 0.015* (0.009) | 0.028*** (0.007) | 0.007 (0.016) |
| Evaluation at | 25th percentile of birth rate | median of birth rate | 75th percentile of birth rate | mean of birth rate | mean of birth rate |
| Individual controls | Yes | Yes | Yes | Yes | Yes |
| County fixed effects | Yes | Yes | Yes | Yes | Yes |
| Year (of conception) fixed effects | Yes | Yes | Yes | Yes | Yes |
| County-specific linear time trends | Yes | Yes | Yes | Yes | Yes |
| Observations | 257,499 | 257,499 | 257,499 | 264,014 | 34,623 |
| R-squared | 0.0056 | 0.0056 | 0.0056 | 0.0059 | 0.0201 |
Note: Birth rate is calculated as the number of births divided by the number of women aged 15–49 in the county during the year when the mother became pregnant. Individual controls include mother’s ethnicity, education, maternal age at conception and its squared term, gestation length and indicators for the timing of initial prenatal care visits. County fixed effects are separate indicator variables for each county. Year fixed effects are indicators that allow for unrestricted differences in year-to-year changes. Reported in parentheses are standard errors clustered by county.
↵* denotes statistical significance at the 10 percent level, ** at the 5 percent level,
↵*** at the 1 percent level.