​The American Community Survey (ACS), an ongoing nationwide survey conducted by the U.S. Census Bureau, uses multiple mail contacts to encourage residents in sampled addresses to self-respond. This report presents a strategic framework for messaging in the ACS mail materials. The framework recommends distinct messaging themes for each mailing to build a conversation with prospective respondents across mail pieces. The framework is the product of a cross-disciplinary literature review and research on messaging conducted by the Census Bureau.