Abstract
Many developing countries collect on the weight for age of children attending health facilities as one element of a nutrition surveillance system. This study compares the estimates of malnutrition from seven health clinics in northern Malawi with estimates derived from nearby community-level surveys. The results show that prevalence of underweight in clinics does not accurately reflect community prevalence. Clinic estimates often differ by two- to threefold from community estimates, and the direction of the bias is not constant across clinics, making these data an invalid basis for targeting programmes according to nutritional need. Similar results were reported in five other studies in the literature, indicating that the Malawi results are not unusual. It is suggested that, contrary to current practice, cross-sectional clinic-based data should be assumed invalid for targeting purposes unless proved otherwise in a given country. Trend data at regional and country levels require further validation.