The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Juvenile body mass estimation: Challenges, issues, and new directions

LIBBY W. COWGILL.

Department of Anthropology, University of Missouri, Columbia

March 26, 2015 , Gateway Ballroom 2 Add to calendar

Two attempts have been made to develop body mass prediction formulae specifically for immature remains: Ruff (2008) and Robbins et al. (2010). While both were developed from the same reference population, they differ in their independent variable selection; Ruff (2008) used measures of metaphyseal and articular surface size, whereas Robbins et al. (2010) relied on cross-sectional properties. Both methods perform well on independent testing samples; however, subtle differences between the two methods exist in the predicted values.

This paper evaluates the differences in the body mass estimates from these two methods in seven geographically diverse skeletal samples under the age of eighteen (n=476). The purpose of this analysis is not to assess which method performs with greater accuracy or precision; here, differences between the two methods are used as a heuristic device to focus attention on the unique challenges affecting the prediction of immature body mass estimates in particular. The two methods differ by population only in some cases, which may be a reflection of body proportions, activity variation, or nutritional status. In addition, body mass estimates vary across age categories, as cross-sectional properties almost always produces higher estimates than metaphyseal surface size. This highlights the difficulty in teasing apart information related to body mass from that relevant to loading, particularly when the original reference population is urban/industrial. The comparison to these two methods of prediction not only provides information about the nature of body mass prediction in juveniles, but also sheds light on issues in immature physiology as well.