My understanding - and I spend a lot of time with teachers - is that this probably isn't true. Teachers improve for the first 3 to 5 years, but most don't after

My understanding - and I spend a lot of time with teachers - is that this probably isn't true. Teachers improve for the first 3 to 5 years, but most don't after that, as very few spend time on ongoing professional development, and there are very few novel experiences they're exposed to. At least some references in: http://www.economist.com/news/briefing/21700385-great-teaching-has-long-been-seen-innate-skill-reformers-are-showing-best http://www.economist.com/news/briefing/21700385-great-teachi...