Yglesias on the inconsistent stories told by the teachers unions.
[there] is a huge consistency problem in the messaging coming out of teachers unions. Sometimes I hear from union-affiliated folks that it’s unfair to attribute differences in student learning to differences in teacher skill, because everyone knows that socioeconomic and home environment factors drive a lot of this. Other times I see the American Federation of Teachers building a messaging program around the idea that its members are Making A Difference Every Day. To me this leads to the obvious conclusion that while socioeconomic and home environment factors do drive a lot of student learning, teachers are also making a difference every day. And it makes a lot of sense to ask which teachers are making the most difference. The teachers who are in the top 20 percent of difference-makers are playing a vital role to the future of America, and we ought to pay them more money and make sure they don’t leave the profession. But the teachers who are in the bottom percent of difference-makers are doing us little good, and we should try to replace them with other people.
Read the whole thing, he makes a number of good points.