This document is about a technical appendix that describes the imputations and edits performed on the March 2021 Current Population Survey (CPS) Auxiliary Data to provide detailed estimates of employer-sponsored health insurance coverage for the 2020 calendar year. It covers steps taken to impute the source of coverage (current vs. former employer), whether the current employer offers coverage, the sector and size of the employer providing coverage, the funding status and plan type, the partition of COBRA vs. retiree coverage, Medicare secondary payer status, actuarial values, union sponsorship, and coverage through a health insurance exchange.