Impacts of two public preschool programs on school readiness in San Francisco

•We studied the short-term impacts of two public preschool programs in California.•Programs included needs-based preschool and Transitional Kindergarten.•We matched students who attended preschool to otherwise similar kindergarteners.•Both programs had positive impacts on school readiness at kindergarten entry.•Transitional Kindergarten was especially effective for students’ literacy skills.