It appears that Raj Chetty, of the very famous and mostly hypothetical Chetty et al. study addressing teacher quality’s impact on students’ lifetime earning potential, had a big influence on the Vergara case in California:

But one has to wonder how much impact that testimony would have had if the judge had considered that most reviews of the study find it to be poppy-cock (see Baker on the Chetty et al. molehill and Di Carlo) or if we simply displayed the numbers differently.

A 40-year “lifetime earnings” of $50,000 is only about $1250 a year, or about, after taxes, $75-80 per month, or about 1.5 to 2 tanks of gas a month.

Hmmmm. Compared to the $50,000 of hypothetical life-time earning or that insane $1.4 million for a class of 28, 1.5-2 tanks of gas a month appears to be much ado about nothing.

Chetty also fails to make a very important point about the economics of investing in measuring teacher quality: It will cost billions of dollars in public funding to create and implement a significant increase in high-stakes testing in order to hypothetically raise the monthly earning income of students enough for them to buy 1.5-2 tanks a gas each month.

A much more effective strategy would be to take those billions of dollars needed to create and implement VAM and give every worker in the U.S. $75 per month tax free. Simple, direct, and guaranteed.

Setting aside that this is all hypothetical, seems a ridiculously inefficient cost/benefit analysis of addressing a teacher quality issue that already is only about 10-15% of measurable student learning.