In 1998, the New Jersey Supreme Court began a series of rulings in the Abbott v. Burke school finance case that led to the design and provision of state-funded high-quality preschool education for children starting at age three. The first children to receive this program were those living in 31 high-poverty urban school districts in New Jersey, known as "Abbott districts." The New Jersey Department of Education (NJDOE) oversees this state preschool program which is provided by school districts and by Head Start and private providers contracting with districts. To support the program, the NJDOE developed high standards for quality, improved the workforce through training and certification, and invested in state-of-the-art facilities. Currently, over 53,000 students attend full-day, high-quality preschool in New Jersey through various providers. From 2003 to2017, the National Institute for Early Education Research (NIEER) conducted periodic evaluations that provide measures of quality over time in the Abbott Districts. This brief examines changes in observed quality across the years. (author abstract)