Fertility decline in a US population favoring large families: A hazard-model analysis of the effect of sib death on Amish fertility

This paper uses proportional hazards techniques and population data from a directory of the Old Order Amish of the Lancaster, PA settlement. It examines the effect of death of the immediately prior sibling on the risk of childbearing for up to 11 children. Prior research typically has pooled data for maternal cohorts. In contrast, separate models are estimated for each maternal cohort. The results are based on all reported first marriages of Amish women born between 1884–1973 (N = 4066). Hazard models run separately for children of each birth order reveal that net of maternal age and length of the prior birth interval (and other statistical and design controls), the death of the prior sib significantly increases the risk of a subsequent birth for the lower birth orders. Separate models by maternal cohort show that sib death increases the risk primarily for later cohorts. The pattern of effects from child mortality and other variables suggests changes in fertility behavior among the Amish, who have strong, traditional norms opposing contraception and favoring large families.