It would seem sensible that the most effective, experienced teachers in a school should teach the students who need the most support and have the most catching up to do. But, we all know that is not what actually happens, that in fact the best teachers are often awarded the easiest students to teach.

A new report from the Calder Center confirms that novice and less effective teachers--as measured by their value-added scores--are the ones teaching lower-achieving students with more behavior and attendance problems. Students entering a new grade with strong math scores were assigned the best teachers; students with low scores were assigned to the weakest teachers. And, across all grades from kindergarten through grade 12, teachers with 10 to 20 years of teaching experience were more likely to teach the easiest students.

The assignment disparity isn't just about effectiveness or even experience. Female and minority teachers of equal ability to their white male counterparts still tend to receive more challenging class assignments.

It is well understood that principals will use choice class assignments as a means for rewarding the good teachers. About a quarter of the principals in this study admitted to the practice. This study posits that the converse is also true, that principals are using assignments as a means to punish the bad, hoping it will drive them away.

Which brings us to applaud Pittsburgh, where the school district is trying to upend this ritual with a cohort of 9th graders, generally thought to be the most challenging and 'at-risk' of the high school bunch. The initiative, known as the Promise-Readiness Corps, has matched 9th graders, all of whom attend eight troubled Pittsburgh schools, with teams of top teachers--some of whom transferred from other schools to be a part of the program. These teachers are earning bonuses of $9,300 for not only teaching these kids, but for agreeing to put in extra time to keep them from falling through the cracks. We'll track its progress.