The Estimation of Unwanted Fertility: Development of a New Method

John B. Casterline, Pennsylvania State University
Laila El-Zeini, American University in Cairo

The estimation of unwanted fertility is a major objective of demographic surveys, including the Demographic and Health Surveys [DHS]. Levels and trends in unwanted fertility are important input to the formulation of population policy, and they are used in the evaluation of family planning programs. Yet the existing methods, by common agreement, possess important deficiencies. We have developed a new method for the estimation of unwanted fertility that in most settings will suffer from less downward bias than existing methods (Casterline & el-Zeini 2005). The method is simple to apply and makes minimal data demands, in particular relying on the most valid and reliable attitudinal item (prospective fertility preferences). This paper addresses the remaining obstacles to widespread use of the new method: calculation of wanted and unwanted TFRs; robustness to trends in fertility preferences; sampling errors; and performance in diverse reproductive regimes, including various lifetime patterns of unwanted births.