Note: Thank you Matt Jones, CSU Dominguez Hills for the heads up.
Emily Hanford of NPR has a nice article about physicists, who are lecturing less and getting better results. Be sure to also click on the link "Listen to the Story"for the radio broadcast.
http://www.npr.org/2012/01/01/144550920/physicists-seek-to-lose-the-lecture-as-teaching-tool
Physicists have collected data providing evidence that learning gains are better when students are deeply engaged in the subject and allowed to collaborate with peers. Sandra Laursen, University of Colorado Boulder, also has data collected at the college level from mathematics courses. Laursen's results are in alignment with this article. Laursen's group has a number of findings. Among the long list of findings, there is statistically significant evidence suggesting the more an instructor talks the less their students learn. (Link to Colorado Study).
As Ed Parker says, "See What They Can Do."