Clare McFadden1, Marc F Oxenham1. 1. School of Archaeology and Anthropology, Australian National University, Canberra ACT 2601, Australia.
Abstract
OBJECTIVES: The objectives of this study were to develop a new subadult-adult ratio for application to sites with good infant representation and to produce an equation to estimate the total fertility rate for a population based on the age-at-death ratio. A new approach is required as current methods exclude the 0-4 years age category due to presumed underenumeration of infants. While this is true for some skeletal samples, others experience good infant representation. MATERIALS AND METHODS: Using age-at-death data and total fertility rates for 52 countries from the United Nations database for the year 1960, we examined the correlation between three age-at-death ratios and the fertility rate. We also utilized linear regression to determine an equation for calculating total fertility rate from the ratio. RESULTS: We achieved a correlation of 0.848 between our D0-14/D Ratio and actual fertility rates. This correlation was significantly higher (p < .05) than the other ratios examined, including the d5-14/d20+ by Bocquet-Appel and Masset () and the 15 P5 index by Bocquet-Appel (). DISCUSSION: The exclusion of infants can result in inaccurate demographic measures, particularly where subadults aged over 5 years of age experience robust survivorship. In addition to providing a solution for sites with good infant representation, this study indicates that the 0-4 years of age category possesses great predictive power when compared to other age categories. The regression equation provides a total fertility rate which is comparable with data regardless of their temporal origin. This method will provide more accurate demographic measures for bioarcheological sites with good infant preservation.
OBJECTIVES: The objectives of this study were to develop a new subadult-adult ratio for application to sites with good infant representation and to produce an equation to estimate the total fertility rate for a population based on the age-at-death ratio. A new approach is required as current methods exclude the 0-4 years age category due to presumed underenumeration of infants. While this is true for some skeletal samples, others experience good infant representation. MATERIALS AND METHODS: Using age-at-death data and total fertility rates for 52 countries from the United Nations database for the year 1960, we examined the correlation between three age-at-death ratios and the fertility rate. We also utilized linear regression to determine an equation for calculating total fertility rate from the ratio. RESULTS: We achieved a correlation of 0.848 between our D0-14/D Ratio and actual fertility rates. This correlation was significantly higher (p < .05) than the other ratios examined, including the d5-14/d20+ by Bocquet-Appel and Masset () and the 15 P5 index by Bocquet-Appel (). DISCUSSION: The exclusion of infants can result in inaccurate demographic measures, particularly where subadults aged over 5 years of age experience robust survivorship. In addition to providing a solution for sites with good infant representation, this study indicates that the 0-4 years of age category possesses great predictive power when compared to other age categories. The regression equation provides a total fertility rate which is comparable with data regardless of their temporal origin. This method will provide more accurate demographic measures for bioarcheological sites with good infant preservation.
Authors: Jennifer C French; Philip Riris; Javier Fernandéz-López de Pablo; Sergi Lozano; Fabio Silva Journal: Philos Trans R Soc Lond B Biol Sci Date: 2020-11-30 Impact factor: 6.237