Teacher evaluation has emerged as a major focus for reform at the highest levels of education policymaking, and for good reason. Most evaluations are based on scant evidence of actual effectiveness, produce inflated ratings, and provide teachers with little useful feedback. This paper offers policymakers and practitioners important "lessons learned" from TAP: The System for Teacher and Student Advancement. The TAP system is a comprehensive strategy to boost teacher effectiveness through opportunities for career advancement, professional growth, performance evaluation, and competitive compensation. TAP represents the longest sustained and most successful effort to radically transform teacher evaluation using multiple measures, including student achievement gains, in the United States today. Since its inception in 2000-2001, the TAP system has grown to serve over 10,000 teachers and 100,000 students across the country, and it will expand to reach twice that many teachers and students by the 2011-2012 school year. TAP uses a comprehensive approach to teacher evaluation which considers multiple measures of performance including student achievement gains in addition to teachers' instructional practices. Recent analyses have shown that TAP's evaluation system produces much more valid performance ratings than do traditional teacher evaluations. TAP's observational measure of classroom instruction represents a true distribution of teacher performance even before "value-added" student learning gains are calculated. TAP's Training and Certification for Evaluators is appended. (Contains 10 figures.)