Using the Coale-McNeil Model for the Study of Postponement of First Births

Dimiter Philipov, Max Planck Institute for Demographic Research

Postponement of births has recently become a significant constituent of fertility change. On the macro-level, it is usually studied by following shifts in the mean age at birth, and shifts in the fertility schedule. On the micro-level, researchers frequently employ hazard models. However, changes in the hazard of a birth potentially confuse tempo and quantum effects. This report suggests the usage of the Coale-McNeil model. Its parameters (mean, variance, and level) make possible an explicit delineation of effects of covariates on fertility tempo and quantum. These parameters are connected to recent studies of tempo and quantum due to Bongaarts and Feeney whose formula is based on changes in the mean age, and Kohler and Philipov who added the variance effect. The model is applied for the estimation of effects of covariates. We suggest the usage of the CM model as a baseline distribution in hazard modelling.