1. This result does not include Gansu, Qinghai, Ningxia Hui Autonomous Region, and Xinjiang Uighur Autonomous Region, which had very few one-child certificate holders, none of whom had gone on to have a second child.
2. All of the analyses in this section were also carried out for currently married, fecund, nonmenopausal women under age 50, since these are the women at risk of becoming pregnant. These results are almost identical with the findings for all married women under age 50 (not shown), since few women in this age group with one child have reached menopause or are infecund. Freedman et al. (1986) suggest that the contraceptive prevalence rates for the survey were too high in some provinces, perhaps because women who had discontinued contraception still reported that they were current contraceptive users at the time of the survey. However, this fact should not affect our results, since there is no reason to believe that the degree of overestimation would be different for women with different family compositions.