Long-term impact is an assumed goal of most educational programs. But, most evaluation designs do not include data collection beyond short-term outcomes. This paper focuses on the value of collecting data regarding the long-term outcomes and impact of a teacher induction program on beginning teachers and mentor teachers. The New Teacher Center provides comprehensive induction systems for new teachers to improve their effectiveness, retention, raise student achievement, and encourage leadership. Our induction programs are built around certain beliefs, one of which is that high quality induction impacts teachers and their practice far beyond their first years of teaching. Two studies were conducted to explore long-term outcomes and impact for both beginning teachers and the mentors who received ongoing professional development. Ways in which attention to long-term impact has many useful purposes in addition to providing evidence of positive impact beyond the life of the program will be discussed. #Non-ProfitsandFoundationsEvaluation #Impact #Prek-12EducationalEvaluation #induction #2011Conference #QualitativeMethods #teacherdevelopment #mentoring