Evaluating Methods for Detecting Fertility Control: Coale and Trussell's Model and Cohort Parity Analysis

In their attempts to distinguish empirically between the innovation/diffusion and adaptation views of fertility transition, researchers have pointed out that evidence of fertility control practised by a significant proportion of women in pre-transition populations would render claims that fertility fell as a result of innovative behaviour less convincing. This paper uses simulation techniques to evaluate the ability of two indirect measures of fertility control, Coale and Trussell's model (M & m) and Cohort Parity Analysis (CPA), to identify the presence or absence of fertility controllers, as well as to detect changes in the extent of control. We conclude that neither M & m nor CPA can be relied on to identify accurately a minority of controllers in a population of interest. These findings suggest the need for a reassessment of some of the evidence cited in the debate over alternative theories of fertility decline.