Cross-platform program for likelihood-based statistical comparisons of mortality profiles on a triangular graph

The construction of mortality profiles to investigate age-at-death patterns is a typical component of most faunal analyses. While many methods exist for constructing and comparing mortality profiles, plotting the percentages of juvenile, prime, and old individuals on a triangular graph, or ternary diagram, remains a popular method for making comparisons. Typically, these comparisons are made visually, but because sample sizes are often small, any differences may be the product of sampling rather than meaningful contrasts in depositional history. To overcome this problem, here we present a likelihood-based method for making statistical comparisons of mortality profiles on a triangular graph, and we make available a cross-platform computer program that implements the method. Although we developed the method with mortality profiles in mind, in principle, it can be used to analyze any kind of artifact for which there are three distinct categories.