A number of indices have been used in recent years to calculate lifespan variation, each with different underlying properties. Although these indices are assumed to be interchangeable, little research has been conducted to show under which conditions this assumption is appropriate, or how to...

A number of indices exist to calculate lifespan variation, each with different underlying properties. Here, we present new formulae for the response of seven of these indices to changes in the underlying mortality schedule (life disparity, Gini coefficient, standard deviation, variance,...

Perturbation analysis examines the response of a model to changes in its parameters. It is commonly applied to population growth rates calculated from linear models, but there has been no general approach to the analysis of nonlinear models. Nonlinearities in demographic models may arise due to...