This factsheet is one in a series about the state of quality improvement systems (QISs) in the United States. Data for the factsheets are from the Quality Compendium, a catalog of the quality initiatives and quality rating and improvement systems (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. The Quality Compendium uses the term “QIS” to be more inclusive of the range of quality supports available across the country. In 2021, there were 45 fully operational QISs in the United States. Forty-two of those communicate a program’s level of quality through a rating component. (author abstract)