Spatial Pattern and Determinants of Age at Marriage in Nigeria Using Geoadditive Survival Model

Ezra Gayawan, Redeemer's University
Samson B. Adebayo, Society for Family Health

In developing countries, timing of first marriage is not only of socio-economic and demographic variables, but varies across regions and districts. We use geoadditive hazard model that allows for measuring spatial effects while incorporating non-parametric terms for the baseline and non-linear effects of continuous covariates to examine spatial patterns in timing of first marriage in Nigeria. The non-linear and baseline effects are modeled by Bayesian penalized splines; spatial components are treated as correlated random effects following a Markov random field while we assumed diffuse priors for fixed effects. Inference is Bayesian and based on the efficient MCMC technique. Application is based on data from 1999, 2003, and 2008 Nigeria Demographic and Health Surveys. Findings show that marriage is early and universal in Nigeria, and the timing is positively associated with education and urbanization and depends on religion. It presents a clear North-South divide.