The D0‐14/D ratio: A new paleodemographic index and equation for estimating total fertility rates

Abstract

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.

Excavating among the megaliths: recent research at the ‘Plain of Jars’ site 1 in Laos

“…A high percentage (11/18, 61 per cent) of individuals were infants and children, with almost half of these dying at the foetal stage or in early infancy. The D0-14/D ratio of 0.61 suggests that fertility was high (McFadden & Oxenham 2017), as is often typical of a growing population. We acknowledge the intrinsic issues of estimating demographic aspects from a small skeletal sample taken from a small part of a wider cemetery.…”

The impacts of underenumeration and age estimation error on the D0–14/D ratio and palaeodemographic measures

“…Infant and elderly underrepresentation and age-estimation have historically been problematic for palaeodemography, with the traditional approach being to intentionally omit infants from palaeodemographic measures. The results reported here show that correlations between the total fertility rate, rate of natural increase and the D0-14/D ratio remain robust even with minimal representation of each age category, however, this alone does not mean our methods (McFadden and Oxenham, 2018a;2018b) are suitable for underrepresented samples. In terms of practical application, where infant underenumeration or elderly underenumeration is suspected our palaeodemographic equations maintain accuracy when up to 25% of the sample is missing, based on the results of the standard error estimates.…”

“…To test the practical value of the original equations when applied to differentially represented samples, the D0-14/D ratios for the omission, underrepresentation and incorrectly aged scenarios were calculated, and then the total fertility rate and the rate of natural increase were estimated using our standard equations (McFadden and Oxenham, 2018a;2018b). For underrepresentation, the impacts of removing 75%, 50% and 25% of the relevant sub-samples were evaluated.…”

A manifesto for palaeodemography in the twenty-first century

“…Demographic proxy estimators therefore provide the most robust-if somewhat generalized-skeletally derived palaeodemographic measures. An improved estimator for fertility [63] as well as new estimators for population increase [64] and for maternal mortality [65] are important recent additions to the skeletal palaeodemography toolkit, although the long-recognized problem of the distorting influence of the under-representation of infants and the elderly in skeletal assemblages [66] on the resultant demographic signature persists [67].…”