The Halley band for paleodemographic mortality analysis

Abstract

This paper suggests a computer aided procedure for the direct transformation of an age at death distribution into a stationary Halley type life table, which can be used for the mortality analysis of skeletal populations. It is based on demographic methods and takes into consideration the uncertainty given by the wide age ranges estimated for each of the individual skeletons. The main difficulty connected with the mortality analysis of a prehistoric graveyard is the wide age range of the age estimations based on morphological age traits in the skeleton, whose width for each of the skeletons within a population depends on the state of preservation and the applied methods for age estimation. The method developed here is based on the idea of the Monte Carlo simulation in extracting a random age at death out of the given age range for each skeleton in order to construct a stationary life table population. If this procedure is repeated for a sufficient number of extractions, this will lead to a relatively narrow bundle of Halley type life tables, characterizing the specific mortality pattern of the observed skeletal population and including the uncertainty resulting from the individual age estimations. The limits of the final Halley band can be defined by including only the inmost 95% of age-specific l(x) values for the single Halley type life tables. A number of test simulations show that this method provides robust and informative results for paleodemographic mortality analysis © 2008 Springer Science+Business Media B.V.