Child anthropometry in cross-sectional surveys in developing countries: an assessment of the survivor bias.

In cross-sectional surveys, the sample of children with anthropometric measurements is not representative of all children in a birth cohort, since only children surviving to the survey date are measured. This survivor bias may have implications for studies of trends and differentials in anthropometric indicators. In this paper, the effects of the survivor bias on the estimates of child anthropometric indicators are assessed by 1) reviewing evidence from longitudinal studies on the prevalence of malnutrition among deceased children and among surviving children and by 2) analyzing retrospective data on child mortality and cross-sectional data on child anthropometry in 17 national surveys that are part of the Demographic and Health Surveys Program. It is concluded that comparisons of anthropometric data across geographic units, population subgroups, and calendar time are marginally affected by the survivor bias, unless mortality differences between the birth cohorts are very large (e.g., well over 50 per 1,000 births).