Many social policy and education programs start from the assumption that people act in their best interest. But behavioral science shows that people often weigh intuition over reason, make inconsistent choices, and put off big decisions. The individuals and families who need services and the staff who provide them are no exception. From city offices and community colleges to the White House, more and more organizations are using research about how people make decisions to improve their work and the lives of those they serve. In 2015, MDRC launched the Center for Applied Behavioral Science (CABS). CABS combines MDRC's 40-plus years of expertise in policy research with the cutting edge of behavioral science. CABS has already completed several large-scale behavioral field studies, incorporated behavioral science into broader MDRC initiatives, and educated policymakers and practitioners on how to use behavioral science to improve their programs. This issue focus presents CABS in developing low-cost solutions to improve public policy.