This study is one of a series of publications of the National Household Survey Capability Programme of the United Nations Statistics Division, Department of Economic and Social Affairs, DESA. The series is designed to assist countries, particularly developing countries, in planning and implementing household surveys. A number of studies have been published to provide reviews of issues and procedures in specific areas of household survey methodology and operations and in selected subject areas. Chapter 1. Types of populations covered by study -- Chapter 2. Estimating the prevalence of a rare characteristic -- Chapter 3. Sampling rare populations -- Chapter 4. Sampling mobile and elusive populations.