Leading up to the 2020 round of censuses, the U.S. Census Bureau is releasing a series of technical notes on Select Topics in International Censuses. Each note highlights a new subject, method, or operation relevant to census planners in middle- to low-income countries. These notes complement the U.N. Principles and Recommendations on Population and Housing Censuses by describing some topics in more detail. Sponsored by the U.S. Agency for International Development (USAID), the Select Topics in International Censuses series is designed for staff in national statistical offices to assist them in addressing some of the significant issues in the 2020 round of censuses.