On teachers, Gates says that after 3 years, a teachers' performance generally doesn't change.
He put up a graph of what influences teachers' performance. By far the greatest effect came from 'past performance,' distantly followed by a having a math degree (for math teachers), and Teach for America experience. Almost negligible came the last item, 'having a masters degree.'
Next, Gates looked at the incentive structure within schools -- it's primarily seniority based, with a bonus if someone has a master's degree.
He noted that good teachers leave the system at a rate slightly higher than that of bad teachers.
He contrasted charter schools such as KIPP (http://www.kipp.org/), where the school evaluates teachers on their performance -- with the traditional model.
The traditional model contractually limits how schools can evaluate their teachers, for example, a principal is contractually not permitted to sit in on a teacher's class more than a few times a year (sometimes even once per year), and even those times, the principal must provide advance notice. Gates compared this to running a factory with some workers "making crap" but the management being banned from observing them without prior notice, so that the workers "might actually try and fool you into thinking we're doing a good job in that one brief moment."
Gates next noted that even a teacher wanted to improve -- can't. New York, for example, passed a law banning schools using teacher improvement data to determine tenure.
Gates closed noting his optimism, praising the testing data for revealing something. He posited the idea of using digital video to record all public school classrooms to give teachers the opportunity to review their work and consult with each other to improve. Gates said: "By thinking of this as a personnel system we can do it much better."
He mentioned _Work Hard, Be Nice_, a book about KIPP: http://www.amazon.com/Work-Hard-Be-Nice-Promising/dp/1565125... Gates said he sent everyone at the TED talk a free copy.
He finished by saying he thought "education is the most important thing to get right for the country to have as strong a future as it should have." He mentioned the House-version of stimulus bill had funding for "these data systems," but the Senate version took that out, because "there are people threatened by these things." He reiterated his optimism, however, saying that people were beginning to recognize the importance of education.