This document summarizes a study comparing Medicaid enrollment data from the Medicaid Statistical Information System (MSIS) to survey data from the Current Population Survey (CPS) to understand discrepancies between the two data sources. The study found the CPS significantly undercounted Medicaid enrollment compared to MSIS data. Measurement error in the CPS, particularly issues with question design and sample coverage, appear to contribute most to the undercount. Further analysis is still needed to fully understand and address the differences between the data sources.