Why Test Scores CAN'T Evaluate Teachers

From the National Education Policy Center. the entire post is well worth a read, here's the synopsis

The key element here that distinguishes Student Growth Percentiles from some of the other things that people have used in research is the use of percentiles. It's there in the title, so you'd expect it to have something to do with percentiles. What does that mean? It means that these measures are scale-free. They get away from psychometric scaling in a way that many researchers - not all, but many - say is important.

Now these researchers are not psychometricians, who aren't arguing against the scale. The psychometricians as who create our tests, they create a scale, and they use scientific formulae and theories and models to come up with a scale. It's like on the SAT, you can get between 200 and 800. And the idea there is that the difference in the learning or achievement between a 200 and a 300 is the same as between a 700 and an 800.

There is no proof that that is true. There is no proof that that is true. There can't be any proof that is true. But, if you believe their model, then you would agree that that's a good estimate to make. There are a lot of people who argue... they don't trust those scales. And they'd rather use percentiles because it gets them away from the scale.

Let's state this another way so we're absolutely clear: there is, according to Jonah Rockoff, no proof that a gain on a state test like the NJASK from 150 to 160 represents the same amount of "growth" in learning as a gain from 250 to 260. If two students have the same numeric growth but start at different places, there is no proof that their "growth" is equivalent.

Now there's a corollary to this, and it's important: you also can't say that two students who have different numeric levels of "growth" are actually equivalent. I mean, if we don't know whether the same numerical gain at different points on the scale are really equivalent, how can we know whether one is actually "better" or "worse"? And if that's true, how can we possibly compare different numerical gains?

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News for March 9th,2011

As the first House committee meeting for SB5 got underway, the Dispatch reports that it is expected to easily gain passage, that of course would eventually setup a referendum to overturn this radical law that upsets decades of collective bargaining. To gain that "easy passage" however, more radical steps were taking by the majority

House Speaker William G. Batchelder replaced two Republicans on the committee: Reps. Richard Adams of Troy and Ross McGregor of Springfield. Unlike in the Senate, where committee changes were made to get the bill passed, House GOP leaders said the changes were made because the two need to focus on the Finance Committee, which will start budget hearings next week.

Business Journal Daily has some of the political implications of this radical legislation

Republicans might have made a mistake by using a sledgehammer when a scalpel might have been more appropriate, Sracic said. Rather than going after collective bargaining rights, which recent poling shows Americans largely support, Republicans could have gone after retirement contributions or other issues, "things that would have been acceptable," he said. "The problem [for Republicans] is unions have been very good about making this about their right to collective bargaining," he remarked.

Swing voters in the middle also tend to act as governors in the system, "so any sort of extreme action is going to be resisted," he added.

In response to Governor Kasich's first state of the state, a crowd of over 3,000 people protested this ongoing assault on working people, as the Latern reports

Thousands of protesters flooded the lawns in an attempt to drown out Gov. John Kasich as he gave his State of the State address.
After encouragement from protest leaders, hundreds of protesters filed into the Statehouse at about noon today. The protesters were in opposition of Kasich and Senate Bill 5.

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