This factsheet is one in a series about the state of quality rating and improvement systems (QRISs) in the United States. Data for the factsheets are from the Quality Compendium, a catalog of the quality initiatives and QRISs operating in early childhood education (ECE) programs in the United States. The Quality Compendium houses data from 2014, 2015, 2016, 2017, 2019, and 2021. While the Quality Compendium uses the term “QIS” to be more inclusive of the range of quality supports available across the country, this factsheet uses the term “QRIS” because it refers only to systems that have a rating component. In 2021, there were 42 fully operational QRISs in the United States. (author abstract)