This paper validates Supplemental Poverty Measure (SPM) estimates from the American Community Survey (ACS) by comparing them with Current Population Survey (CPS ASEC) estimates for 2009–2023. The ACS SPM has exceeded the CPS SPM every year since 2011, reaching a 2.3 percentage-point gap in 2023. Imputed medical expenses account for a large share of this gap, while other SPM elements also show systematic differences in receipt rates and amounts. The paper recommends imputing health insurance premiums at the health insurance unit level, as well as refining imputation models. It also offers diagnostic tables and figures for annual ACS SPM production.