Rate of natural population increase as a paleodemographic measure of growth

The aim of this study was to provide a verifiable measure of population increase from age-at-death data. It was anticipated that the D0-14/D ratio would be a good predictor of the rate of natural increase (births minus deaths) due to its strong relationship with the total fertility rate. United Nations age-at-death data for 58 countries was used to calculate the rate of natural population increase and evaluate its relationship to the D0-14/D ratio. Additionally, the impact of migration on both the rate and the ratio was measured. A correlation of r = 0.863 (95% CI 0.777–0.917) between the D0-14/D ratio and rate of natural population increase was found. Linear regression provided a simple equation for calculating the rate of population increase. The rate of natural population increase accounts for the disparity (or lack of) between births and deaths, and provides a valuable measure for evaluating ancient population variability. While the rate does not factor in migration, we believe migration should be measured independently as it is not always of interest to bioarcheological research questions and has a negligible impact on the rate of natural increase and the D0-14/D ratio. Estimating the rate of natural population increase has the potential to provide significant insights into past populations and the human response to change.