On some properties of the preceding birth technique.

The preceding birth technique (PBT) in which mothers who have second or higher-order birth are asked about the survival status of their previous live-born child is a simple procedure for measuring childhood mortality. The authors used Demographic Surveillance System data from Matlab Bangladesh to investigate some properties of the PBT estimate. Life table mortality for ages 0-6 years of each of the birth cohorts from 1982-89 and the corresponding proportion of preceding children dead by the time of birth of the children of these birth cohorts were estimated and compared. The authors conclude that the PBT estimate is a good approximation to q the time reference of the PBT estimate in months before the most recent birth will be the duration of the birth interval following death of the preceding child less the age at death of that preceding child and the PBT estimate will poorly describe the trend in infant mortality if it and 1-3 years-old mortality change at different rates.