I will protect your pensions. Nothing about your pension is going to change when I am governor. - Chris Christie, "An Open Letter to the Teachers of NJ" October, 2009

Sunday, March 17, 2013

NJ Teacher Evaluation: Math Fail #2

I ask again, as I did before:

Do the Broad-funded interns at the New Jersey Department of Education understand math?

When the NJDOE rolled out their new teacher evaluation system, Operation Hindenberg Achieve NJ, they included a slideshow to help explain how their proposals would work.

Slide 14 (annotations mine):

Slide 20:

OK, wait a minute...

Slide 14 says my students' Student Growth Percentiles, or SGPs, will be calculated on a scale of 1 to 99. We've already established that my evaluation will use the Median SGP for my class, even though that is potentially a hugely distorted metric (see NJDOE Math Fail #1 for more). But Slide 20 has an example where a teacher gets a "raw score" of 2.0 for their mSGP.

How in the hell did the NJDOE calculate this number?

The NJDOE can't be saying this teacher got a 2 out of 99 for their mSGP; if that were the case, the "weighted score" would be a lot lower. Did they "translate" the mSGP in this example to a "2.0"? If so, what was the original mSGP? Was it "50"?

And why is the "raw score" expressed to two significant digits? Is it possible to get a "2.1"? How many more SGP "points" would it take to move up to that? Where are the cut points in SGPs for moving from one SGP "raw score" to the next? What is the research basis for determining those cut points?

Do you folks at NJDOE understand how arbitrary this is? Do you understand you are violating basics of mathematics and statistics here? Do you care?

There will come a day when state regulations force a school administrator to make a high-stakes decision based on this ill-conceived nonsense; that's when the lawsuits will start. This could have been avoided, if the NJDOE, Governor Chris Christie, and Education Commissioner Cerf had listened to the substantive criticisms of people who study this stuff and know what they are talking about.

Instead, they asked former editors of nightlife magazines to lead their "reform" efforts. What comes next is inevitable...

NJ Teacher Evaluation - Code Name: Operation Hindenberg


Galton said...

"Do you folks at NJDOE understand how arbitrary this is? "
Popoff and Schulman surely understand how badly flawed the metrics are. Will they have the courage to talk and explain it to Bari and Tracey? Not likely. As for the rest, (Cerf, Matheny, Fiscaro) they are not equipped to understand.
I would like to see one of our journalists ask these folks, if this system is fair, mathematically sound and wise. We hear yammerings about "status quo", "building airplanes in-inflight" and even Cerf's "we have to try something", but will any of these folks vouch for this system personally?

Most importantly,
Jazzman, you are a state-wide treasure. Few can go as deep, stay on point, and cut through the BS as well as you.
Again, many thanks!

Duke said...

Appreciate that, Galton - and all of your great comments, here and elsewhere.