Friday, November 30, 2012

More Evidence That VAM Is Junk Science

by Diane Ravitch

New York is very proud of its new Educator Effectiveness Evaluation model, which claims to measure which teachers and principals are effective, relying in part on the increase (or not) of test scores of students.

Bruce Baker of Rutgers demonstrates that the model is biased and inaccurate. It favors classes and schools that start off with higher-performing students.

(See original report, click here.)

He concludes with a brief sermon about the importance of ethics:
"I have pointed out that the originators of the SGP approach have stated in numerous technical documents and academic papers that SGPs are intended to be a descriptive tool and are not for making causal assertions (they are not for “attribution of responsibility”) regarding teacher effects on student outcomes. Yet, the authors persist in encouraging states and local districts to do just that. I certainly expect to see them called to the witness stand the first time SGP information is misused to attribute student failure to a teacher."

"But the case of the NY-AIR technical report is somewhat more disconcerting. Here, we have a technically proficient author working for a highly respected organization – American Institutes for Research – ignoring all of the statistical red flags (after waiving them), and seemingly oblivious to gaping conceptual holes (commonly understood limitations) between the actual statistical analyses presented and the concluding statements made (and language used throughout)." 

"The conclusions are WRONG – statistically and conceptually. And the author needs to recognize that being so damn bluntly wrong may be consequential for the livelihoods of thousands of individual teachers and principals! Yes, it is indeed another leap for a local school administrator to use their state approved evaluation framework, coupled with these measures, to actually decide to adversely affect the livelihood and potential career of some wrongly classified teacher or principal – but the author of this report has given them the tool and provided his blessing. And that’s inexcusable."

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