After New York City encouraged principals to be more deliberative in awarding tenure, ineffective teachers were more likely to leave schools or the profession voluntarily—to the benefit of students, according to a recently released working paper.
Even though the overall percentage of teachers actually denied tenure did not change much, the more-rigorous process appears to have reshaped the workforce—suggesting that changes in practice rather than underlying tenure laws, may bear fruit, said Susanna Loeb, a Stanford University professor and one of the study's authors.
"Within current tenure laws, there's quite a bit of flexibility that districts aren't using in order to improve their workforce. This did not require a change in the law; it simply required a change in practice," Loeb said. "It wasn't necessarily greeted warmly by everyone involved, but you didn't need a court case or legislative change to change practice, and I think that's true in a number of places."
The paper comes during a period of intense interest in tenure. A California judge recently struck down a teacher-tenure law in that state, and it is unclear whether the state legislature will seek modifications. Two other states—Florida and Kansas—have outlawed tenure; South Dakota, Idaho, and North Carolina have unsuccessfully tried to do so.
Yet there has been next to no empirical research on just how alterations in tenure laws affect student achievement.
The paper, issued earlier this week, examines an unusual change in New York City policy. In 2009-10, the city education department revised what had been a more or less automatic process of granting tenure. The district started supplying more data on teachers to principals, asking them to weigh performance observations, reviews of teachers' lesson plans, and in limited instances "value-added" data based on test scores. And it began requiring principals to justify their decisions about whether to grant or deny tenure—particularly if it didn't match up with the data. Principals could also extend the tenure decision for another year if they weren't ready to make a final call.
For the study, Loeb and her co-authors looked at tenure decisions made between 2010-11 and 2011-12, matching it to the demographics and SAT scores, and preparation routes of the teachers. Then, they looked at how those teachers performed either on observations or using a value-added method, controlling for student attributes.
Here are the findings:
- The number of teachers denied tenure was very low, but far more teachers that had their probationary period extended under the new policy, and the number of teachers approved for tenure dropped sharply. (See the figure, below.)
- Having one's probationary period extended increased the likelihood that a teacher would move to a different school, or quit teaching in New York City, relative to those teachers in the same school granted tenure.
- "Extended" teachers who chose to leave were less effective, on both principals' judgment and value-added measures. What's more, their replacements would have on average been somewhat stronger teachers.
- Teachers in schools with high concentrations of black and low-performing students were more likely to be "extended," and it isn't entirely clear whether that was because such schools have poorer-quality teachers or because principals in such schools were harder graders. (Research has unveiled a bias toward tougher grading of teachers of minority students.)
In sum, "nudging" some teachers out the door this way seems to have improved the overall quality of the teaching force.
Of course, teacher effectiveness is a complicated matter. I asked Loeb about how to balance her findings with other, separate research she's conducted that shows that teacher turnover of any sort is generally harmful to academics.
"It depends on the long-run effect of these policies. If what they do is increase the quality of teaching in the schools, they become more appealing places to teach. So I think we have to look at more than the one-year effect," she said.
Another key takeaway, Loeb added, are that evaluations matter because, when used in a non-formulaic way, they can supply information for such decisions and improve the workforce.
The United Federation of Teachers opposed the new tenure practices at the time, and a spokesman said the union is still reviewing the research. But on first glance, it underscored the different results in schools with certain demographics.
"We have a chicken-and-the-egg problem here," union spokesman Dick Riley said. "Were people less likely to have probation extended because their kids are more successful, or is it the other way around?"
He added that it isn't clear whether teachers who transfered, but remained in the district, ultimately got tenure.
"What happens to the people who change schools? If they got tenure, then what you have is a difference of opinions among the principals."