Estimating infant mortality trends from child survivorship data

Summary Brass's procedure for estimating mortality from census or survey data on numbers of children born to women by age group and numbers of children surviving is generalized to allow the estimation of mortality trends. The new procedure is applied to data for Costa Rica and peninsular Malaysia. The resulting infant mortality rate estimates are compared with rates calculated from vital registration figures. The comparisons suggest, surprisingly, that the estimates derived from statistics for women aged 30-50 are not noticeably inferior to those derived from those for women aged 20-30. This suggests that the common practice of disregarding statistics for women aged over 30 or 35 years may be a mistake. Figures are presented which suggest that estimates based on women aged less than 20 are likely to be very seriously biased because of differential infant mortality by age of mother at birth.