15; SIMPLIFIED GENERAL METHOD FOR (CLUSTER-SANllabE SURVEYS OF WEALTH IN DEVELOPING GObfNTIFSfilES

In order to monitor the health status of the popuiation and to evaluate the use and effectiveness of disease protection and control measures, up-to-date information is required. In developing countries in paflicular, the information needed is often provided by means of cross-sectional surveys. An example of such a survey is that developed by the Expanded Programme on lmmunization (EPI) of the World Health Organization (WHO) (7, 2:) to estimate vaccination status among young children. This scheme is a type of cluster sampling, in which a sample of 30 clusters (villages or the like) is setected and 7 children of the required age are selected in each cluster. The scheme was designed to ailow the estimation of vaccination status to within 210 percentage points and achieves this aim very well (1, 3). It has been used for its intended purpose of estimating vaccination coverage in many parts of the world (1).