Bayesian factor models for probabilistic cause of death assessment with verbal autopsies

The distribution of deaths by cause provides crucial information for public health planning, response, and evaluation. About 60% of deaths globally are not registered or given a cause which limits our ability to understand the epidemiology of affected populations. Verbal autopsy (VA) surveys are increasingly used in such settings to collect information on the signs, symptoms, and medical history of people who have recently died. This article develops a novel Bayesian method for estimation of population distributions of deaths by cause using verbal autopsy data. The proposed approach is based on a multivariate probit model where associations among items in questionnaires are flexibly induced by latent factors. We measure strength of conditional dependence of symptoms with causes. Using the Population Health Metrics Research Consortium labeled data that include both VA and medically certified causes of death, we assess performance of the proposed method. Further, we propose a method to estimate important questionnaire items that are highly associated with causes of death. This framework provides insights that will simplify future data collection.