Last May Benedic Carey published a very interesting article in the NY Times about how collaboration in the classroom increases testing scores. http://www.nytimes.com/2011/05/13/science/13teach.html?_r=1
"The research comes from a closely watched group led by Carl Wieman, a Nobel laureate in physics at the University of British Columbia who leads a $12 million initiative to improve science instruction using research-backed methods for both testing students’ understanding and improving how science is taught" said Carey. Today Prof. Wieman is at the Univeristy of Colorado.
It looks like programs such as POGIL "Process Oriented Guided Inquiry Learning" that are helping college educators and to certain degree high school teachers are the way to go.