Small Area Estimation of Fertility: Comparing the 4-Parameters Own-Children Method and the Poisson Regression-Based Person-Period Approach

Abstract

This study assesses the capabilities of the 4-parameters own children method (4-pOCM) approach in the estimation of fertility rates of small areas using Schoumaker’s (2013) Poisson regression-based person-period approach (PPA). The paper was designed to appraise the Excel toolkit designed by Garenne and McCaa (2017) to implement the 4-pOCM in relation to Schoumaker’s (2013) Stata software command tfr2 which implements a Poisson regression-based PPA to calculate fertility rates. Using a descriptive approach, analyses were conducted on the 2015 Zimbabwe Demographic and Health Survey, applying the two tools and methods to the estimation of national and subnational fertility rates. The results showed that the 4-pOCM was able to maintain consistency in its estimates between national to subnational levels just like the proven tfr2. The study concluded that the 4-pOCM can be a reliable reference method for studying fertility trends of small areas especially in African contexts where reliable vital registration data are limited.