On a popular economics site, fivethirtyeight.com, authors use “hard numbers” to tell compelling stories, and this time the compelling story told is about value-added models and all of the wonders, thanks to the “hard numbers” derived via model output, they are working to reform the way “we” evaluate and hold teachers accountable for their effects.
In an article titled “The Science Of Grading Teachers Gets High Marks,” this site’s “quantitative editor” (?!?) – Andrew Flowers – writes about how “the science” behind using “hard numbers” to evaluate teachers’ effects is, fortunately for America and thanks to the efforts of (many/most) econometricians, gaining much-needed momentum.
Not to really anyone’s surprise, the featured economics study of this post is…wait for it…the Chetty et al. study at focus of much controversy and many prior posts on this blog (see for example here, here, here, and here). This is the study cited in President Obama’ 2012 State of the Union address when he said that, “We know a good teacher can increase the lifetime income of a classroom by over $250,000,” and this study was more recently the focus of attention when the judge in Vergara v. California cited Chetty et al.’s study as providing evidence that “a single year in a classroom with a grossly ineffective teacher costs students $1.4 million in lifetime earnings per classroom.”
These are the “hard numbers” that have since been duly critiqued by scholars from California to New York since (see, for example, here, here, here, and here), but that’s not mentioned in this post. What is mentioned, however, is the notable work of economist Jesse Rothstein, whose work I have also cited in prior posts (see, for example, here, here, here, and here,), as he has also countered Chetty et al.’s claims, not to mention added critical research to the topic on VAM-based bias.
What is also mentioned, not to really anyone’s surprise again, though, is that Thomas Kane – a colleague of Chetty’s at Harvard who has also been the source of prior VAMboozled! posts (see, for example, here, here, and here), who also replicated Chetty’s results as notably cited/used during the Vergara v. California case last summer, endorses Chetty’s work throughout this same article. Article author “reached out” to Kane “to get more perspective,” although I, for one, question how random this implied casual reach really was… Recall a recent post about our “(Unfortunate) List of VAMboozlers?” Two of our five total honorees include Chetty and Kane – the same two “hard number” economists prominently featured in this piece.
Nonetheless, this article’s “quantitative editor” (?!?) Flowers sides with them (i.e., Chetty and Kane), and ultimately declares victory for VAMs, writing that VAMs ultimately and “accurately isolate a teacher’s impact on students”…”[t]he implication[s] being, school administrators can legitimately use value-added scores to hire, fire and otherwise evaluate teacher performance.”
This “cutting-edge science,” as per a quote taken from Chetty’s co-author Friedman (Brown University), captures it all: “It’s almost like we’re doing real, hard science…Well, almost. But by the standards of empirical social science — with all its limitations in experimental design, imperfect data, and the hard-to-capture behavior of individuals — it’s still impressive….[F]or what has been called the “credibility revolution” in empirical economics, it’s a win.”