Select school districts in San Mateo County, California have offered a suite of services to children from low-income families that includes high-quality preschool, family engagement, summer learning, and a focus on attendance. This intervention, made up of combined services provided from preschool through third grade, is referred to as Big Lift. Two sets of observed outcomes data are analyzed in this report: the data from the 2016 kindergarten class through third grade, and the kindergarten readiness of the kindergarten classes of 2016, 2017, 2018, and 2019. Outcome measures included rates of participation and several school- and development-related measures at kindergarten entry and up to third grade.