Congratulations Ohio corporate education reformers, you have discovered yet another way to measure poverty. Unfortunately you seem to believe this is also a good way to evaluate teachers.

Value-added was supposed to be the great equalizer -- a measure of schools that would finally judge fairly how much poor students are learning compared with their wealthier peers.

Meant to gauge whether students learn as much as expected in a given year, value-added will become a key part of rating individual teachers from rich and poor districts alike next school year.

But a Plain Dealer/StateImpact Ohio analysis raises questions about how much of an equalizer it truly is, even as the state ramps up its use.

The 2011-12 value-added results show that districts, schools and teachers with large numbers of poor students tend to have lower value-added results than those that serve more-affluent ones.

Of course there are going to be defenders of the high stakes sweepstakes

"Value-added is not influenced by socioeconomic status," said Matt Cohen, the chief research officer at the Ohio Department of Education. "That much is pretty clear."

That is the same Matt Cohen who admitted he is no expert and has no clue how Value-add is calculated

The department’s top research official, Matt Cohen, acknowledged that he can’t explain the details of exactly how Ohio’s value-added model works. He said that’s not a problem.

“It’s not important for me to be able to be the expert,” he said. “I rely on the expertise of people who have been involved in the field.”

Perhaps if Mr Cohen became more familiar with the science and the data he would realize that:

Value-added scores were 2½ times higher on average for districts where the median family income is above $35,000 than for districts with income below that amount.
For low-poverty school districts, two-thirds had positive value-added scores -- scores indicating students made more than a year's worth of progress.

For high-poverty school districts, two-thirds had negative value-added scores -- scores indicating that students made less than a year's progress.

Almost 40 percent of low-poverty schools scored "Above" the state's value-added target, compared with 20 percent of high-poverty schools.

At the same time, 25 percent of high-poverty schools scored "Below" state value-added targets while low-poverty schools were half as likely to score "Below."

Students in high-poverty schools are more likely to have teachers rated "Least Effective" -- the lowest state rating -- than "Most Effective" -- the highest of five ratings. The three ratings in the middle are treated by the state as essentially average performance.

Is there really any doubt what is truly being measured here? Ohio's secret Value-added formula is good at measuring poverty, not teacher effectiveness.

We predict districts and administrators and those connected to the development of Value-added measures are going to be deluged with lawsuits once high stakes decisions are attached to the misguided application of these diagnostic scores.