A major innovation for the 2020 U.S. Census was the use of administrative records
(ARs) to enumerate some households. Methodology developed at the U.S. Census
Bureau used ARs to classify some addresses as Occupied, Vacant, or Nonresidential and to create a roster of the residents with their characteristics for some of the addresses classified as Occupied. The Census Bureau began a research program in 2012 to pursue its goal of identifying a methodology for using administrative records to reduce the cost of the 2020 Census Nonresponse Follow-up (NRFU) operation while preserving data quality. NRFU is the census field operation where enumerators visit addresses that did not submit a self-response and attempt to obtain an interview. This document provides a high-level discussion that includes more details regarding the evolution of the methodology for AR enumeration and its implementation in the 2020 Census. By focusing on data quality during each phase of the research, development, and implementation, the chosen methodology enabled using ARs to enumerate 4.59 percent of the addresses. The investment in AR enumeration proved to be essential to the success of the 2020 Census.