"Now, raise your hand if you would trade income for job security, ceteris paribus." (AP/Steve Ruark)

Tenure in public schools is under attack from critics who argue that the system protects incompetent teachers and holds back students. Earlier this year, a judge threw out California's tenure laws, holding that they barred students of color from getting an equal education. Tenure had the effect of concentrating bad teachers in schools in impoverished, urban neighbors, the judge found in the case, Vergara v. California. Following that ruling, education reformers filed a similar suit in New York.

For Jesse Rothstein, a former Obama administration economist and an expert on the quality of instruction in public schools, the hubbub around tenure is beside the point. Getting good teachers in front of classrooms is tricky, and Rothstein argues it would still be a challenge without tenure, possibly even harder. There are only so many people willing to consider teaching as a career, and getting rid of tenure could eliminate one of the job's main attractions. 

Wonkblog spoke with Rothstein by phone on Monday. An edited transcript of the interview is below. Next week, we'll be speaking with David Boies, an accomplished litigator who recently joined the legal effort against tenure.

There's general agreement that principals in urban school districts are having a hard time staffing their schools with talented and effective teachers. I'm wondering if you could talk about that problem in general.

The job is a really hard job. Being an excellent teacher in a really hard setting is very hard, and not many people can do it. That's a dimension that's often been overlooked. A second dimension is that notmany people want to teach in those settings. Again, it's a really, personally difficult job. Many people burn out quickly, and either leave teaching or go find a job in an easier setting. There are very high rates of turnover. A third, related, is that people know it's a hard job, and so it's hard to recruit people into the job. Then, I think, a fourth, which is the premise of the Vergara case, is that there are certainly some teachers in urban, high-poverty settings that are not that good, and we ought to be figuring out ways to either help them get better or get them out of the classroom. But it's important to keep in mind that that's only one of several sources of the problem.

Even if you give the principal the freedom to fire lots of teachers, they won't do it very often, because they know the alternative is worse. You've got to have people in the classrooms -- that's your first priority.

Teacher tenure is of course a somewhat unusual institution. Tenured teachers can be difficult to remove. How do you see this system affecting schools one way or another?

You're right that tenured teachers have a lot of job security. It's hard to remove them -- not impossible, but hard. But if you then ask of people working at large corporations of 1,000 people or more, what percent of them were fired for cause or just laid off, it's about the same magnitude. It's hard to fire people in any large organization. It doesn't happen very much.

The argument that anti-tenure people make is, "Look, there are all these excellent Harvard graduates and Yale graduates or whatever that are now going into finance because it's risky. They like risk, and those people are being repelled from teaching by the lack of risk." The people who are going into finance are not just taking on more risk, but are also getting a lot of reward for that risk. That was in some ways the thrust of my research. You can't think about the risk in isolation. You've got to think about the combination of the pay package and the risk. If you adopt a policy that increases the risk, you're going to have to pay people more to offset that. Maybe that's a good deal, and maybe it's not.

It sounds like you're saying that teacher tenure is just a red herring.

That's generally my view. It's really a red herring. It just doesn't matter that much. If you got rid of tenure, you would find that the principals don't really fire very many people anyway.

Then of course there's the question of evaluating teachers, and I know you've done a lot of research on this issue. Are there methods that are reliable in your view?

There's no perfect method. I think there are lots of methods that give you some information, and there are lots of problems with any method. I think there's been a tendency in thinking about methods to prioritize cheap methods over methods that might be more expensive. In particular, there's been a tendency to prioritize statistical computations based on student test scores, because all you need is one statistician and the test score data. Classroom observation requires having lots of people to sit in the back of lots and lots of classrooms and make judgments.

Why have people focused on value-added? I think that's a complicated question. It seems scientific, in a way that other methods don't. Partly it has to do with the fact that it's cheap, and it seems like an easy answer.

The value-added metric, though, points to the importance of teachers in general in an economic sense, maybe if it's not all that useful for evaluating them individually. I'm thinking of Raj Chetty's research with John Friedman and Jonah Rockoff. They argue that a single teacher can have a really large financial impact on the future of their students. I'm curious about what you think about that research.

I don't think anybody disputes that good teachers are important, that teachers matter. I have some methodological concerns about that study, but in any case, even if you take it at face value, what it tells you is that higher value-added teachers' students earn more on average. It doesn't tell you at all what other measures of teacher effectiveness would be associated more or less strongly with long-run outcomes. What we're after is a proxy for a teacher's overall effectiveness. At best we have evidence on one of the potential proxies, but we don't have evidence on any of the others -- classroom observations, portfolio reviews, student evaluations. There's any number of things that teachers do that are not very well covered by multiple choice end of year tests in math and reading: helping students with behavioral problems; teaching subjects that aren't covered by the tests, creativity, and higher order thinking.

Everyone agrees that the goal should be to make teaching a respected profession, a profession that talented and able people want to enter. So far, I've heard you say that there's not a lot of evidence suggesting ways that that could be accomplished effectively. Is there one policy that we haven't discussed?

We could double teachers' salaries. I'm not joking about that. The standard way that you make a profession a prestigious, desirable profession, is you pay people enough to make it attractive. The fact that that doesn't even enter the conversation tells you something about what's wrong with the conversation around these topics. I could see an argument that says it's just not worth it, that it would cost too much. The fact that nobody even asks the question tells me that people are only willing to consider cheap solutions. They're looking for easy answers, not hard answers.

Is there anything you want to add?

The one thing that I would add is that these decisions about how to change teacher contracts are complicated policy decisions. It's really hard to see how a court is going to be well-situated to think through how do we trade off getting rid of bad teachers versus attracting and retaining people who might be good. On the principle that democracy is the worst form of government except for all the others, I don't have a huge amount of confidence that the legislature will get it exactly right, but they're the body that in our system is empowered to make this sort of complex trade. I don't see an alternative.