Decades of research demonstrate that an early and strong foundation for earning matters. Children who have effective learning opportunities before kindergarten have an advantage in school, and in life, over children who do not, especially children with adverse childhood experiences. Children who attend quality prekindergarten programs are more prepared for school in terms of their daily literacy, language, and math skills, their executive function, and their social-emotional development. In some cases, prekindergarten participants are less likely to be identified for special education services or to be held back in elementary school than children who do not attend developmentally-informed preschool programs that include strong educational components.

Universal Transitional Kindergarten (UTK) refers to the expansion of TK by the school year 2025-2026 to serve all four-year-old children by September 1, of each year, regardless of income, providing a year of rich learning opportunities the year before kindergarten that families can choose from as part of the California's public education system. TK means the first year of a two-year kindergarten program, serving four-year-old children regardless of income, that uses a modified kindergarten curriculum that is age-and developmentally-informed (California Education Code [EC] Section 48000 [d]).