A re-estimation of the multiplying factors for the Brass technique for determining childhood survivorship rates.

Summary One of the truly significant contributions to practical demography is the procedure developed by William Brass for estimating life-table values from minimal data obtained in fertility surveys. Specifically, Brass designed a set of factors dependent on the shape of the fertility schedule, which convert proportions of children dead of women in standard age intervals into life table q(x)-values. Jeremiah Sullivan recently presented in this journal a method for simplifying the calculations involved in obtaining the multiplying factor in the Brass procedure. Both Brass and Sullivan employed restrictive fertility schedules to obtain their multiplying factors, and a rigorous test of either model has been hampered by the lack of numerous adequately recorded fertility schedules, especially those which begin early. Recently, a set of model fertility schedules which adequately duplicates empirical fertility schedules has been developed. These schedules were used to test the Brass and Sullivan procedures and to obtain new estimates of multiplying factors. Although the Brass and Sullivan procedures are shown to produce good estimators, new estimators, which prove superior to either, are developed and analysed.