Publicly funded pre-kindergarten (pre-K) programs are large-scale efforts to provide school-based early childhood education opportunities to preschool aged children. Programs are voluntary and can be for 3- and 4-year-olds, though programs often only or disproportionately serve 4-year-olds. Publicly funded pre-K programs vary from state to state; they can be universally available regardless of family income or focus on specific populations, usually children from low income backgrounds. Programs also vary based on state early learning standards and guidelines for choosing curricula. Public pre-K programs are typically funded by the state but can be funded by cities and school districts. (author abstract)