Lot quality assurance sampling techniques in health surveys in developing countries: Advantages and current constraints

Costly, time-consuming, traditional survey methods usually provide information only at national or regional levels. Information from the health center and community levels is, however, also of interest particularly in managing and directing supervisory activities. An industrial method is described with practical applications for conducting health surveys to monitor health programs in developing countries. This lot quality assurance sampling (LQAS) methodology was developed in industry for quality control, and allows the use of small sample sizes when surveying small geographical or population-based areas. The paper describes the method, explains how to build a sample frame, and how to conduct the sampling necessary for field application of LQAS. Sampling unit selection for health program monitoring is described in detail. Simple- and double-sampling schemes are discussed, as well as interpretation of survey results and the planning of subsequent rounds. Constraints limiting use by health planners are explored with suggestions provided on modes of overcoming obstacles through future research.