Methods for Estimating Incidence Rates and Predicting Incident Numbers in Military Populations

Monitoring of the health of military populations and developing effective personnel management plans relies on the ability to measure and predict the incidence of important events such as attrition, training failures, promotions and transfers between groups. Incidence rates are widely relied on to report the prevalence of these events and for modelling to predict future events. However, calculating and using incidence rates in real-world scenarios is not straightforward, and challenges are frequently encountered. This paper provides a detailed mathematical development of equations that define incidence rates, Bayesian techniques for estimating rates based on the available evidence and quantifying how certain the estimate is, and a beta-binomial model for predicting the variation in future event numbers. These methods do not require significant additional effort or resources to apply in typical military workforce modelling applications, but produce meaningful improvements in the depth and accuracy of the analysis.