Detecting Stopping and Spacing Behaviour in Historical Demography. A Critical Review of Methods

Abstract

Couples who have started to reproduce and subsequently want to limit their fertility can follow two strategies: birth spacing or stopping. Spacing consists of increasing the intervals between successive births, while the stopping strategy attempts to prevent further reproduction altogether after the maximum desired number of children has been reached (Knodel, 1987; Okun, 1995).It is widely accepted among scholars that stopping has played the major role in the European historical fertility transition. This article contributes to the reopened debate about the role of spacing before and during the fertility transition (see Okun, 1995: Hionidou. 1998; Friedlander, Okun and Segal, 1999: Fisher, 2000; Clcgg. 2001). First, it will show how historical research on the fertility transition has been methodologically incapable of detecting intentional spacing behaviour in a convincing manner. secondly, it makes suggestions about the kind of methods to be used in future historical demographic research in order to assess the role of spacing.I. Commonly used methods for detecting stopping and spacingDuring the past decades, several attempts have been made to develop methods for detecting birth spacing in historical fertility data. Most attempts have not been entirely convincing. Yet, even if one assumes that spacing has not demonstrably played an important role in the European fertility transition, there is no hard evidence to the contrary either.Another index of fertility control that has often been used is the mother's age at last childbearing. Although a declining age has generally been interpreted as reflecting stopping behaviour, increased spacing has been shown to reduce age at last birth as well. There has been some controversy regarding the magnitude of that effect (see Knodel, 1987; Anderton, 1989; and the response by McDonald and Knodel, 1989), but simulations have shown that reductions in the mean age at last birth cannot be interpreted uncritically as a sign of stopping behaviour only (Okun, 1995). The same holds for an increase in the length of the last closed birth interval, which has been interpreted as evidence of failed attempts to stop childbearing. However, increased spacing affects all birth intervals, including the last. Since both forms of fertility regulation inflate the ultimate closed interval, research cannot differentiate between stopping and spacing by examining changes in the length of this interval (Okun, 1995).The main point to be made in the following discussion is that the lack of conclusive evidence in favour of or against spacing behaviour is also a consequence of the fact that many historical demographic analyses are carried out at a highly aggregated level. The next paragraphs investigate the consequences of such aggregations on different measures of spacing and stopping.1. Parity progression schedulesA well-known, more elaborate method for detecting fertilityinhibiting behaviour consists of investigating birth intervals as a function of the final number of children born in completed fertility histories (Knodel, 1987; Anderton and Bean, 1985). Some features of the pattern of birth intervals by final parity are true under conditions of natural fertility. First, the length of the intervals is negatively related to the final number of children born. Couples that reach a higher family size have on average shorter birth intervals. Second, within each final parity group, the length of the intervals increases with parity; the interval between the first and the second child is on average shorter than the one between the second and the third, and so on. This is basically a result of decreasing fecundity. Finally, the increase in length between the penultimate and the ultimate interval is greater than the increase between successive intervals at lower parities. This is expected when couples try to stop childbearing but holds as well under conditions of natural fertility. …