The Program for the International Assessment of Adult Competencies (PIAAC) is a multicycle survey of adult skills and competencies sponsored by the Organization for Economic Cooperation and Development (OECD). The survey examines a range of basic skills in the information age and assesses these adult skills consistently across participating countries. The first cycle of PIAAC included three rounds: 24 countries participated in 2011-12 (round 1); 9 additional countries participated in 2014-15 (round 2); and 5 additional countries participated in 2017-18 (round 3). The United States has participated in all three rounds of the first cycle of PIAAC. This report describes the statistical methodology used to produce estimates of average scores and high, middle, and low proficiency levels of adult skills for every state and county in the United States.