Background: Recent growth in subsidized preschool opportunities in the United States for low-income 4-year-old children has allowed federal Head Start programs to fund more slots for 3-year-old children. In turn, when Age-3 Head Start participants turn four, they may choose to switch into one of the many alternative care options or choose to stay in Head Start for a second year. Objectives: We analyze a nationally representative sample of Age-3 Head Start participants to examine whether children who stay in Head Start for a second year at Age 4 exhibit greater school readiness and subsequent cognitive and behavioral performance compared with children who switch out of Head Start into alternative care. We also examine differences between children who stay at the same Head Start center at Age 4 with those who switch to a different Head Start center. Research Design: Child fixed effects analyses coupled with inverse probability of treatment weights to remove observable, time-invariant differences between Head Start stayers and switchers. Subjects: Cohort of Age-3 Head Start attendees from the Head Start Impact Study. Measures: Child cognitive and behavioral skills assessed by trained administrators annually at ages 3-7. Results: Age-3 Head Start participants' outcomes do not differ at the end of preschool, kindergarten, or first grade based on their choice of Age-4 program. Staying at the same Head Start center for 2 years may be beneficial for behavioral skills. Conclusions: For low-income families, there exist many equally beneficial options to support their children's school readiness through public preschool programs. (author abstract)