Purposive Program Placement and the Estimation of Family Planning Program Effects in Tanzania
针对计划生育项目布局非随机导致的效果估计偏差问题，提出一个整合个体生育模型与项目布局动态过程的联立方程方法，并用坦桑尼亚数据证明标准方法会高估医院、低估卫生中心的效果。
Abstract Most studies evaluating the impact of family planning on fertility treat the presence of family planning clinics as being “randomly” assigned among the areas included in the study. They tend to ignore the possibility that the distribution of services may be related to the fertility level observed in a particular area. In some cases the distribution of services may respond to a conscious effort by public authorities or funding agencies to target areas with observed higher fertility. Even in absence of program planning, the factors determining service placement might be related to the determinants of high, or low, fertility in a particular area. If that is the case, and one fails to account for the endogeneity of family planning services, then the estimated impact of family planning programs will be biased. This article presents a modeling approach to address this issue. The model extends the simultaneous equation framework by integrating an individual-level model of timing and spacing of children with the dynamic process of program placement. Individual-level data from the 1991/1992 Tanzania Demographic and Health Survey are augmented with data on the timing of, and factors influencing, family planning service placement to demonstrate the approach. The empirical results show that standard methods yield misleading results on the impact of different components of the family planning program on fertility. In particular, the effect of access to family planning hospitals on births is overstated, and the impact of access to health centers that offer family planning is understated significantly. We quantify the size of these effects through simulations.