The Pioneer ACO project paved the way for the Next Generation and other ACO models. The CMS pioneer ACO model began on January 1, 2012. The project included an initial three-year performance period and allowed for two additional option years. CMS used this model to test alternative model designs with ACOs that were already experienced in shared savings (savings and losses) models. Thirty-two ACOs started the program in 2012. At the end of the program in 2016, only eight ACOs remained. A final evaluation report and quality and financial results from this project are provided on the CMS website at https://innovation. cms. gov/initiatives/Pioneer-ACO-Model/. Review the information in the Final Evaluation Report and the Performance Year 5 data spreadsheet.