To utilize skeletal populations, one must assume stable population conditions at the time of deposition of the skeletons; one must also assume that the sample is representative of the population, and that it is free from systematic aging error. In this chapter, we assume that the studies used satisfy these conditions.

The procedure for calculating mortality rates based on assigned ages of skeletons is simple and straightforward. Table 1 provides an example, the Illinois Hopewell Indians (Blakely 1971). There are 294 specimens distributed over 8 age classes including children. Assuming that this represents the stable mortality experience of any cohort in a non-growing population, a survivorship schedule can be derived.