Most of the school boards in Texas are suing the state because of outrageous budget cuts (over $5 billion in the last legislative session), which caused increased class size. The state called as its witness Grover Whitehurst of the Brookings Institution, to testify that class size doesn’t matter. Whitehurst was in charge of the U.S. Department of Education’s Institute of Education Sciences during the administration of President George W. Bush.
In this account of his appearance, Leonie Haimson of Class Size Matters points out that Whitehurst’s own department–during his time in office–had labeled class size reduction as one of the few truly effective reforms.
Does class size matter? Read this account and reach your own judgment.
Diane Ravitch's blog 
Class size certainly does matter when teachers have little prep and collaboration time. My guess is that these claims about class size are cherry-picked from research produced from tests like PISA. What gets left out is that the countries and cities with high PISA scores and large class size generally have teachers in contact with children significantly fewer hours than in the US. The last PISA analysis maintains that one must pick what economic trade-offs one prefers, either larger class sizes with fewer contact hours and more prep for teachers, or smaller class sizes with less prep and collaboration. Those “reformers” who maintain class size doesn’t matter are being disingenuous. They are basically saying you can get something for nothing by presenting half-truths.
I teach in a small school district and class size can vary tremendously from year to year. I have had as few as 11 and as many as 23 elementary students in my class. I can tell you from personal experience that class size dies matter. That anyone can say otherwise astounds me.
Make that DOES matter. My iPad and I are arguing about spelling and it always wins!
If there is no limit in class size, then sky will be the limit. Check out what happened to me in Florida when the state Legislature exempted advanced placement classes from the twice voter approved class size amendment. I ended up with 54 freshmen in one AP class. I don’t care if you are the android “highly effective” Superteacher that Bill Gates claims can handle an unlimited amount of students. You are not the same teacher in a room with 25 students as you are with 54 students. You can read more about it here http://kafkateach.wordpress.com/2012/05/27/class-size-matters.
The only people who say class size does not matter are those who have never taught and why would I listen to them?
I’ve found the class size threshold for effective teaching to be 15 or 16. (This would be a good survey question!) And I definitely consider class size to be one of the top factors in creating an effective classroom.
I agree. Past that point, it seems that each additional student is like another 2-3 students. The social issues and other demands on the teacher seem to grow exponentially. I am speaking from the experience of an elementary school teacher, but I am sure middle and high school teachers would agree.
As a high school teacher, I think 25 is the ideal class size. I can go up to 30, but anything after that becomes unmanageable and a huge amount of class time gets eaten up with administrative tasks like attendance, passing out work, just dealing with the needs of 30 adolescents that all have issues and questions. When I have had small class sizes (once upon time), I noticed I could complete a 90 minute lesson in 60 minutes compared to a large class size where I would always run out of time. Hint, hint, Rahmbo and Arne, maybe a more efficient way to improve student learning would be to reduce class size rather than mandating longer school days or years. We tried that in Miami. Low performing schools had an extra hour and a half added to the day. It turned into a total waste as students and teachers were burned out. Test scores never improved.