The Problem of Teacher Sorting

Four of the main justifications for public education are

  1. subsidizing a vehicle for civic indoctrination (I use a blunt phrase, but on the whole, I think the civic indoctrination done in US public schools is quite a good thing)
  2. subsidizing the acquisition of human capital whose full benefits are not captured by the student in the future (note that even income taxes in the future is enough to create a gap between public and private benefit from education, but in all likelihood there are other not-fully-compensated benefit spillovers as well)
  3. alleviating borrowing constraints that make it hard to pay for  education in advance of earning the wage premium from education and
  4. redistribution.

Public education is a particularly attractive form of redistribution, since unlike direct transfers to poor families, (a) education goes directly to the kids and (b) education tends to encourage, rather than discourage hard work.

But public education is seldom optimized as a means of redistribution. Richer school districts often have better facilities and supplies, and typically offer higher salaries to teachers. But even when nominal teacher salaries are equalized across districts by state law, the greater difficulty of teaching the kids who need teaching the most to catch up often means that disadvantaged kids get worse teachers. (And the lower desirability for a teacher of either living near those schools or commuting further also tends to lead to worse teachers for disadvantaged kids.) To even equalize teacher quality would require paying enough of a salary premium for teaching in difficult schools that the typical teacher would be indifferent between taking on the tougher job with that salary premium or taking on an easier job with a lower salary. And an argument can be made that the very best teachers (in terms of being able to motivate kids and teach the most basic and important concepts well) should be teaching the kids who are the furthest behind.

The chickens have now come home to roost. The failure of California to address the problem of teacher sorting led to a remarkable decision yesterday by a Los Angeles Superior Court. As reported in the Wall Street Journal article linked above:

In a closely watched court case that challenged California’s strong teacher employment protections, a group of nine students have prevailed against the state and its two largest teachers unions.

A Superior Court here on Tuesday found that all the state laws challenged in the case were unconstitutional. The verdict could fuel similar lawsuits in other states where legislative efforts have failed to ease rules for the dismissal of teachers considered ineffective.

The student plaintiffs in Vergara v. California argued that the statutes protecting teachers’ jobs serve more often to keep poor instructors in the schools—hurting students’ chances to succeed.

Citing the Supreme Court’s landmark 1954 Brown v. Board of Education “separate but equal” ruling, Superior Court Judge Rolf M. Treu wrote in his decision that the laws in the case “impose a real and appreciable impact on the students’ fundamental right to equality of education.” The decision also agreed with the plaintiffs’ arguments that the poorest teachers tend to end up in economically underprivileged schools and “impose a disproportionate burden on poor and minority students.”

It is easy to get drawn into the debate about the merits of teacher tenure. But I hope people don’t miss the problem of teacher sorting. If many of the worst teachers in a state ended up in the richest school districts, I think it would bring home to wealthy and influential voters the importance of school reform–in many dimensions. Then maybe poor kids would have a chance, as they not only got average rather than below-average teachers, but the average teacher and school performance improved. 

Update: I received some great comments on the Facebook version of this post (which was really only a link to the post here):

Robert FloodPublic schools are not allowed to pay a premium in $ or in class size or load to induce teachers to go where their product is highest. So, to keep the best teachers, they bid with school assignments. My wife, in the last 10 or 15 years of her teaching career taught math to the best kids in Montgomery Co MD - maybe the richest country in the US. The kids were great and the parent support was superb - except for the nutsy parental “grade stalkers.” Her biggest problem with teaching was “up county” administration. The admin grew much faster than the # of kids or # of teachers.

My advice - let schools bid for teachers. I also think that when we see diseconomies of scale in administration, i.e., admin growing faster than the administered, , the teachers need to be consulted and help to design administration.

Chris KimballI recently read (in Malcolm Gladwell’s “What the Dog Saw”, although there’s surely a source behind that) that the range for least effective to most effective teachers runs from ½ (year’s worth of material in one year of class) to 1-½ (year’s worth of material in one year of class). Notwithstanding a raft of questions about the data (is it valid, what does the distribution look like, can the extremes be replicated, etc.) the extent of that range was a wake-up for me–making teacher sorting and selection a much more important issue than I had been thinking.