Political and legal battles surrounding teacher tenure and seniority have been raging in California over the past couple of years. In 2014, in Vergara v. California, a Los Angeles County Superior Court judge ruled that a variety of teacher job protections worked together to violate students’ constitutional right to an equal education. This past spring, in a 3–0 decision, the California Court of Appeals threw this ruling out. The American Prospect’s Rachel Cohen interviewed Jesse Rothstein, the former chief economist at the U.S. Department of Labor and a current public policy and economics professor at the University of California, Berkeley, who testified during the Vergara trials in defense of California’s teacher tenure and seniority statutes. This conversation has been edited and condensed.
Rachel Cohen: Your research suggests that even if we got rid of teacher tenure, principals still wouldn’t fire many teachers. Why?
Jesse Rothstein: It’s basically because in most cases, there’s just not actually a long list of people lining up to take the jobs; there’s a shortage of qualified teachers to hire. If you deny tenure to someone, that creates a new job opening. But if you’re not confident you’ll be able to fill it with someone else, that doesn’t make you any better off. Lots of schools recognize it makes more sense to keep the teacher employed, and incentivize them with tenure.
It’s all about tradeoffs. If you get rid of tenure and start laying off lots of teachers, and you don’t do something else to make the job more attractive, then you won’t get enough teachers. I’ve studied this, and it’s basically economics 101. There is evidence that you get more people interested in teaching when the job is better, and there is evidence that firing teachers reduces the attractiveness of the job.
One of the central debates in California is how long the probationary period should be before teachers can be eligible for tenure. Reformers want to lengthen the process, and you’ve argued that two years is long enough to make that call.
Suppose you go to a new restaurant the first week it opens up and it’s terrible. It’s possible you just got a bad draw. But you don’t really need to go five more times. If it’s bad enough the first time, you just don’t go again. Sometimes you need to go one more time if it’s an okay restaurant, and you’re not sure if it’s just above the line, or just below it. And for those cases, there’s some value in waiting longer.
During the Vergara trial there was a debate over what would happen if we lengthened the probationary period, and whether principals would wait until the end of the clock to fire a bad teacher, or if they would they fire a lot of bad teachers at the end of their first year. I argued that it was unreasonable to expect the principals to make the firing decisions before they had to. It’s a lot harder to say, “I’m confident this teacher wouldn’t work out” than it is to say, “Well let’s just give it a little more time.”
So you’re saying that if we lengthen the probationary period to five years, there’s a greater chance a principal wouldn’t fire a bad teacher until year five?
If you think, as I do, that the principals will wait until the end, until a decision is forced on them, then a longer clock means you get more accurate decisions, but the bad teachers are kept around longer. So you have to weigh those two things. And what I found is you don’t get much or any benefit from lengthening the clock unless you’re planning on firing lots and lots of teachers—around 40 percent. If you’re planning on only firing the bottom 10 percent or 15 percent of teachers, though, you’re better off doing that quickly even though sometimes you may fire a teacher in the bottom 30 percent, rather than the bottom 5 percent. You won’t have as much information to be quite as accurate, but you’ll usually be right, and you’ll get the bad teachers out faster.
Aren’t most teachers pretty bad their first year? Are we denying them a fair shot if we make tenure decisions so soon?
Even if they're struggling, you can usually tell if things will turn out to be okay. There is quite a bit of evidence for someone to look at. That’s why the novice teachers who will eventually turn out to be good are better, on average, during their first year than the novice ones who will be bad.
These debates over firing bad teachers often ignore all the teachers who voluntarily leave the profession. Teaching is a hard job, and if someone is bad at it, very often they aren’t trying to stay in the classroom.
Yes, teachers who leave on their own, or are counseled out, are downplayed. Part of that is because we don’t have very good data on them. Most people don’t tend to write on their exit forms the reason why they are leaving.
Value-added models (VAM) played a significant role in the Vergara trial. You’ve done a lot of research on these tools. Can you explain what they are?
[The] value-added model is a statistical tool that tries to use student test scores to come up with estimates of teacher effectiveness. The idea is that if we define teacher effectiveness as the impact that teachers have on student test scores, then we can use statistics to try to then tell us which teachers are good and bad.
VAM played an odd role in the trial. The plaintiffs were arguing that now, with VAM, we have these new reliable measures of teacher effectiveness, so we should use them much more aggressively, and we should throw out the job statutes. It was a little weird that the judge took it all at face value in his decision.
When did VAM become popular?
I would say it became a big deal late in the [George W.] Bush administration. That’s partly because we had new databases that we hadn’t had previously, so it was possible to estimate on a large scale. It was also partly because computers had gotten better. And then VAM got a huge push from the Obama administration.
It’s very controversial and I’ve argued that one of the flaws of it is that even though VAM shows the average growth of a teacher’s student, that’s not the same thing as showing a teacher’s effect, because teachers teach very different groups of students.
If I’m a teacher who is known to be really good with students with attention-deficit disorder, and all those kids get put in my class, they don’t, on average, gain as much as other students, and I look less effective. But that might be because I was systematically given the kids who wouldn’t gain very much.
So you’re skeptical of VAM.
I think the metrics are not as good as the plaintiffs made them out to be. There are bias issues, among others. One big issue is that evaluating teachers based on value-added encourages teachers to teach to the state test.
During the Vergara trials you testified against some of Harvard economist Raj Chetty's VAM research, and the two of you have been going back and forth ever since. Can you describe what you two are arguing about?
Raj’s testimony at the trial was very focused on his work regarding teacher VAM. After the trial, I really dug in to understand his work, and I probed into some of his assumptions, and found that they didn’t really hold up. So while he was arguing that VAM showed unbiased results, and VAM results tell you a lot about a teacher’s long-term outcomes, I concluded that what his approach really showed was that value-added scores are moderately biased, and that they don’t really tell us one way or another about a teacher’s long-term outcomes.
So I published a paper responding to Chetty’s work, and he responded to my paper saying it didn’t hold up. I then published another paper, saying his critiques didn’t hold water, and he’s due to respond. So it’s still ongoing.
Could VAM be improved?
It may be that there is a way to use VAM to make a better system than we have now, but we haven't yet figured out how to do that. Our first attempts have been trying to use them in not very intelligent ways.
What’s wrong with the way we evaluate teachers now?
We haven't taken very seriously the need to evaluate teachers, and we have probably not taken seriously enough the importance of good school management. Principals are often just appointed among the teacher corps, and not given much training. They’re put in the job, and left to sink or swim. There is a good argument that we've got to take that job more seriously, and a big part of that job is evaluating, mentoring, and helping teachers get better. And in a lot of places, we haven’t taken the tenure decision very seriously; we just don’t do careful assessments.
In general I felt the Vergara plaintiffs were blaming the statutes for the fact that the schools themselves were not well managed.
You’ve made the argument that these teacher job protection debates have to be considered in terms of tradeoffs. Can you say more?
In general I don’t think people have confronted these tradeoffs around making quick decisions versus more accurate decisions, around layoffs and the value of job security, and building a stronger school.
This is particularly true with teacher salaries. The way teacher salaries are currently structured is that we don't pay new teachers very much and we make up for that by having a fair amount of wage growth over the course of a career. I think there are good reasons for that, and it helps people stay in the job for longer. But you can only do that if you can make a commitment to people that they’ll have their job for years. They will accept years of low pay in exchange for higher pay down the line. Experienced teachers are better, on average, but they’re also more expensive.
If I’m a new teacher and I’m being underpaid, and I can’t count on that being made up to me later, it’s less likely I will accept that bargain. So there are tradeoffs to having less job security.
It’s been two years since the Vergara trial. Do you think anything’s changed?
I guess in general there's been a little bit of a political walk-back from the push for VAM. And this retreat is not necessarily tied to the research evidence; sometimes these things just happen. But I’m not sure the trial court opinion would have come out the same if it were held today.
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