Like most states, Maine is facing staffing shortages. Recent Maine Education Policy Research Institute (MEPRI) studies have documented--both quantitatively and qualitatively--some of the challenges that schools face in filling teacher positions. In this report the authors focus on the supply of educators and assess the feasibility of using administrative data from the certification system to identify shortage areas. Specifically, they combine certification and staff data to quantify the number of certificate holders who are working in their endorsement area, working in education outside of their endorsement area, or not working in Maine's education sector (i.e. potentially available for hire) to get a rough sense of demand and supply. They give special attention to teacher shortage areas including math, science, special education, world languages and English language acquisition.