On Friday, DCPS announced performance ratings for employees under the IMPACT evaluation system, now two years old. Most of the headlines have surrounded the firings of 413 employees (288 for poor performance), but little has been said about the distribution of those scores. We compared the ratings distribution of this year to last year, noticing something very interesting. No, look...

There's a lot of talk--and policy--these days directed at fostering "effective teaching" to boost student achievement. You would think there was a common definition of effective teaching, or an agreed upon way to determine which qualities and approaches make teachers effective, but so far it has proven elusive. Even how to measure effective teaching is a subject of great debate....