Last year, TNTP's The Irreplaceables shed light on the real teacher retention crisis in urban schools: too many of our best teachers aren't given the support they need to stay in the classrooms where they're most needed. Now TNTP has produced a follow-up report, Perspectives of Irreplaceable Teachers, which details the survey results of over 100 of the nation's top teachers. The findings are eye-opening.

One of the most revealing questions asked of these high-flyers was: To what extent do you agree that the following activities have improved the quality of your instruction or helped you be a better teacher? These responses garnered the most agreement:

• My experiences over time trying different lessons and methods of teaching
• Observations of other teachers at work in their own classrooms
• Advice or feedback from teacher colleagues

Responses from these same teachers suggest that the following pre- or in-service training activities were among the least valuable:

• Formal education coursework, such as graduate school
• Formal professional development courses offered by my school
• The teacher preparation I received prior to obtaining my first full-time teaching job

Now, roughly two-fifths of these teachers earned their certification via alternate routes. Nonetheless, it's telling that the programs charged with building teacher capacity, regardless of how they are structured, got such low marks from this group. Kentucky's commissioner of education Terry Holliday certainly took notice of this and offered a post with his takeaways from the report.

Here's our suggestion for a next step: What if researchers from these teacher preparation programs observed these teachers, distilled their best practices and made sure that teacher candidates mastered them? Then all teachers would learn from the best, and future surveys of the nation's best teachers would show how invaluable great training really can be.