This study, published nationally through the Institute for Education Sciences, involves a randomized controlled trial of the Retired Mentors for New Teachers program for probationary teachers developed by Aurora Public Schools (APS) in Aurora Colorado. The program uses recently retired, master educators to support probationary teachers in high-need elementary schools. Data sources include student reading and math assessments, teacher turnover data, and teacher evaluation data. The study found statistically significant impacts on student learning in math after one year. Also included is a program cost and return on investment analysis.