Raising Awareness Among Immunization Programme Managers to the Potential Bias Resulting from the Application of Fixed Factors to Obtain Target Population Size Estimates

Abstract

The challenges faced by many immunization programmes in understanding the size of the target population(s) for their work is seemingly well recognized, although not well documented. Despite the aid of adjustments for differences over time, inadequate information constitutes a major weakness of target population size estimates for many immunization programme managers. Because complete vital registration, the most reliable source for target population data, does not ex-ist in the majority of the low- and middle-income countries [1,2], immunization programmes must estimate the number of children in the target population (e.g., births, surviving infants) based on counts or estimates made by local programme staff or health workers or rely on projections from the latest census data [3].