Teacher induction programs are designed to support new teachers and reduce teacher turnover. Comprehensive teacher induction, however, goes beyond traditional induction by relying on carefully selected and trained full-time mentors and also includes an intensive curriculum involving instructional support and professional development, opportunities to observe experienced teachers, and assessment tools for teachers that permit ongoing evaluation of practice and constructive feedback. Final results from Mathematica’s national evaluation show that compared to business-as-usual induction programs, two years of comprehensive induction can boost student achievement. For teachers who received one year of comprehensive induction, however, there was no impact. The study found no impacts on other outcomes.