Jones, James Holland; Michael D. Gurven and Michael H. Price

Low-dimensional parametric models of human mortality are important tools in biodemography and comparative evolutionary studies. These models allow researchers to smooth mortality data drawn from small samples, which tend to yield volatile estimates of age-specific mortality hazards as a result of limited observations in adjacent age-classes, without imposing particular age-specific patterns. The Siler competing-hazards model is a theoretically-appealing and commonly-used parametric model for human mortality. The Siler model contains five parameters and captures the overall bath tub-shape of human mortality without otherwise making large assumptions about the level of different mortality components. Unfortunately, the model can be quite challenging to fit because of correlations between the different parameters. Gurven and Kaplan (2007) compiled data on the age-specific mortality of hunter-gatherers and other small-scale subsistence populations.