Assessment of the Validity of Assumption of Zero Net Migration in Estimation of Adult Mortality Using Preston Integrated Approach

This study examines the implication(s) of ignoring net migration in estimation of adult mortality from non-stable population using the Preston [1] integrated method and proposes a method of assessing presence of net migration in a study data. In deriving the model for estimation of adult mortality from non-stable population, Preston [1] has assumed that the study population is closed to migration, that is, the net migration is zero or negligible. However, in most developing countries this assumption is not necessarily true. In this study, the method proposed for assessing the need for adjustment for net migration is the ratio (AF) of the observed proportion of mid-period population reported as aged x years (c(x,t)) when net migration is not zero to the corresponding proportion when net migration is zero (