Over two years, teachers were supposed to get 114 “contact hours” of training on how to teach about rational numbers, including summer institutes, one-day follow-up seminars, and in-school coaching visits.
Teachers with one or more years of training did score higher on “knowing what types of graphic representations will best convey specific ideas clearly, and knowing the common student misunderstandings.”
But training didn’t lead to higher student achievement.
Teachers’ general math knowledge, which wasn’t affected by the training, correlated to significantly higher student achievement, the study found.
Masters degrees don't correlate to higher student achievement, either, but I need to get one if I ever want to see a pay raise.