Estimating childhood mortality trends from routine data: a simulation using the preceding birth technique in Bangladesh.

The Preceding Birth Technique (PBT) has been proposed as a method suitable for ascertaining the prevailing level of under-2 mortality in countries without full vital registration. It is a monitoring tool rather than a method that will replace other established approaches to measuring childhood mortality levels and differentials that other demographers have developed over the last 30 years. The principle obstacle to the wider adoption of the PBT is the low proportion of women who give birth in maternity clinics and hospitals. A larger proportion of mothers, however, visit clinics and hospitals for antenatal care and to vaccinate their newborn. We used data from the Matlab surveillance system to test the accuracy of mortality estimates derived using the PBT with data obtained from mothers at antenatal visits and at the vaccination of their youngest children. The study shows that the PBT estimates under-3 rather than under-2 mortality in Bangladesh due to the long birth intervals. The data when used to stimulate the collection of the information at antenatal or postnatal visits, nonetheless provide an accurate description of under-3 mortality trends and differences for the two periods examined--before 1984 and before 1989.