Here's a response Matthew Di Carlo on the Albert Shanker Institute blog, which I expected to be much more critical than it is:

In a new National Bureau of Economic Research working paper on teacher value-added, researchers Raj Chetty, John Friedman and Jonah Rockoff present results from their analysis of anincredibly detailed dataset linking teachers and students in one large urban school district. The data include students' testing results between 1991 and 2009, as well as proxies for future student outcomes, mostly from tax records, including college attendance (whether they were reported to have paid tuition or received scholarships), childbearing (whether they claimed dependents) and eventual earnings (as reported on the returns). Needless to say, the actual analysis includes only those students for whom testing data were available, and who could be successfully linked with teachers (with the latter group of course limited to those teaching math or reading in grades 4-8).

The paper caused a remarkable stir last week, and for good reason: It's one of the most dense, important and interesting analyses on this topic in a very long time. Much of the reaction, however, was less than cautious, specifically the manner in which the research findings were interpreted to support actual policy implications (also see Bruce Baker's excellent post).

What this paper shows – using an extremely detailed dataset and sophisticated, thoroughly-documented methods – is that teachers matter, perhaps in ways that some didn't realize. What it does not show is how to measure and improve teacher quality, which are still open questions. This is a crucial distinction, one which has been discussed on this blog numerous times (alsohere and here), as it is frequently obscured or outright ignored in discussions of how research findings should inform concrete education policy.

The Persistence Of Both Teacher Effects And Misinterpretations Of Research About Them

Posted by Matthew Di Carlo on January 8, 2012

http://shankerblog.org/?p=4708