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Biased teacher study does not stand up to scrutiny, LFT says

(Baton Rouge – September 6, 2012) A study purporting to support a new teacher evaluation system is the product of a biased, pro-business think tank and should not be taken seriously by education reformers in Louisiana, according to the Louisiana Federation of Teachers.

“If this study were to be taken seriously, it would have been published by a peer-reviewed journal instead of by the Manhattan Institute, which prides itself on promoting ‘market-oriented policies’ aimed at privatizing public services,” said Louisiana Federation of Teachers President Steve Monaghan.

In a conference call to reporters, Manhattan Institute Fellow Marcus Winters said that his new report validates the use of the so-called Value Added Model to evaluate teacher performance. Winters said that his research is based on the results of value added data collected in Florida public schools.

The Baton Rouge Advocate quoted Winters’ report as saying that value added models “can be a useful piece of a comprehensive evaluation system” and that “claims that it is unreliable should be rejected.”

Sections of Winters’ report not quoted by The Advocate appear less confident: “VAM is not a perfect measure of teacher quality because, like any statistical test, it is subject to random measurement errors. So it should not be regarded as the ‘magic bullet’ solution to the problem of evaluating teacher performance.”

Another recent report, from the Annenberg Institute at Brown University, goes even further in questioning whether or not a headlong rush to embrace VAM as a primary method of teacher evaluation is a good idea: “(W)hether or not the shift to intensive use of value-added measures of effectiveness will improve our nation’s system of teaching and learning remains to be seen. Indeed, there are good reasons to believe these measures may be counterproductive.”

Mathematician and president of Math for America John Ewing, in a carefully researched article first published in Notices of the American Mathematics Society, warned that the selling of the value added model is a form of “mathematical intimidation” and that the claims that value added measures can predict which teachers will be most successful are unsupported.

Ewing cautioned: "Making policy decisions on the basis of value-added models has the potential to do even more harm than browbeating teachers. If we decide whether alternative certification is better than regular certification, whether nationally board certified teachers are better than randomly selected ones, whether small schools are better than large, or whether a new curriculum is better than an old by using a flawed measure of success, we almost surely will end up making bad decisions that affect education for decades to come."

Monaghan said that there remain serious questions about the way Louisiana’s Department of Education is developing and implementing a Value Added Model of teacher evaluation.

“The department has stonewalled all efforts to discover just how their model was devised,” he said. “The LFT and others have tried without success to get even a glimpse of the formula the state is using to determine a teacher’s value.”

In a response to The Advocate’s article, education researcher Noel Hammatt cited numerous academic studies which conclude that “VAM is rife with difficulties, and that it should constitute, if any, a small part of teacher evaluations. NONE of the major research groups support the use of VAM as 50% of a teacher's evaluation or more, as we have in this state! Not one.”

Said Monaghan, “The jury is still out how well the Value Added Model judges teacher effectiveness. Even Winters’ report acknowledges that VAM ‘is subject to random measurement errors’ and that VAM alone should not be used to make employment decisions.

“Yet Louisiana’s new tenure law does exactly that,” Monaghan said. “Based solely on the VAM portion of a teacher’s evaluation, a teacher can lose tenure, be denied pay raises and be terminated.

“If even biased research like this points out the fallacies in Louisiana’s new tenure law,” Monaghan concluded, “it is obvious that the law must be overturned.

"The Federation suggests," concluded Monaghan, "that those interested in a more reasoned, well researched discussion of the history, current use, and problems with the value added model of assessing teachers should spend some time reading a comprehensive survey of articles on the subject."

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