Team teaching is still around. My wife, for example, team taught for two years. The school she has been at for the last five years has had at least two teams ea

Team teaching is still around. My wife, for example, team taught for two years. The school she has been at for the last five years has had at least two teams each year typically at the second and third grade level. She was at an older school that had very large class rooms which made it possible. Most of the newer schools in my area have no team teaching because the classrooms are simply too small to accomodate two full classrooms of children. As far as empirical evidence on the smaller class room sizes, can't really say much about it. I'll provide a couple of anecdotes from my wife's experience. Larger classroom sizes make it significantly harder to provide personalized help to students during the day, this can be a serious problem if those students don't have anyone at home that can or will help them. At the school my wife has spent the last five years at a good portion of the parents were illiterate and couldn't provide any help to their children though many of them wanted to. Additionally larger classroom sizes can mean significantly more of the teachers personal time (off contract) must be spent on prep, grading, conferences, etc. That was something we had to deal with and significantly impacted our personal lives. One problem with trying to measure the effect of classroom size changes are that they are not the only change being made. Schools change curriculum, lunches, teaching styles and everything else. Some measurements also need to be done over many years. For example, locally about six years ago all day kindergarten was implemented in poorer areas and where second language learners were prevalent. The students that started in that program and were immersed in school activities and english language activities all day just finished fifth grade. Across the board there have been significant improvements in test scores with that group (math scores have been decent, specifically the reading/writing scores went up a large amount). Due to budget issues all day kindergarten is being cut. The reason being that there's no "empirical evidence that all day kindergartens were the cause of the increased performance on test scores." I'm paraphrasing, but it's a common issue in how education is measured and tracked.