Computing mortality statistics on combined groups

Official reports of death rates and other vital statistics provide useful, but sometimes incomplete, demographic information for specific research investigations concerned with mortality. Furthermore, methods for determining these statistics may be unclear and cumbersome to apply. The current paper describes formulas and logical procedures for computing proportions of deaths, death rates, and other vital statistics on combined groups. A simplified approach to finding age-adjusted death rates based on standard frequency distributions is also described. A computer program for facilitating these computations is available from the author.