The purpose of the 2020 Post-Enumeration Survey (PES) was to measure the coverage of the 2020 Census.

The PES was designed to measure the coverage of housing units and people, excluding group quarters, people residing in group quarters, and areas of remote Alaska. It provided estimates of net coverage and components of coverage, including correct enumerations, erroneous enumerations, whole-person census imputations, and omissions. Since the PES was an evaluation, its results did not affect the 2020 Census results.

The Initial Housing Unit (IHU) Matching operation was the first PES matching operation. This operation included three sequential phases: IHU computer matching, IHU Before Followup clerical matching, and IHU After Followup clerical matching.

The IHU Matching operation was designed to resolve the match status of sample addresses relatively early in the decennial census life cycle. This operation compared the list of addresses based on the results of the PES Independent Listing operation to the list of housing units and group quarters based on the census Enumeration MAFXs to find matches, duplicates, and nonmatches, in a computer component and a clerical component.

This assessment report focuses on the IHU Matching operation and identifies lessons learned. Subsequent PES matching and data collection operations are addressed in separate reports. It provides information on the successes and shortcomings of the 2020 PES IHU Matching operation and produces valuable data for the 2030 PES planning cycle.