TNTP, author of the pivotal study called“The Widget Effect,”  has a new report out called “The Irreplaceables: Understanding the Real Retention Crisis in America’s Urban Schools.”  Here’s the full report; here’s the Executive Summary.

“Irreplaceables” are teachers who are so successful that they are “almost impossible to replace,” able to move student growth well beyond a typical teacher. TNTP estimates the number of these superheroes at 20% in diverse urban districts, yet retention is low: “When one of them leaves a low-achieving school, it can take 11 hires to find just one teacher of comparable quality.”

Here’s the reasons why these schools struggle to retain irreplaceable teachers:
1.    Principals make too little effort to retain irreplaceables or remove low-performing teachers.
2.    Poor school cultures and working conditions drive away great teachers.
3.    Policies give principals and instructional leaders little incentive to change their ways.

The report recommends, in part, that each school set a goal of retaining 90% of Irreplaceable teachers, pay them what they’re worth, and protect them during lay-offs..