Here's some data.
http://www.ksg.harvard.edu/PAE/readapae/ Friedrichs.pdf
Great link - thank you. I stand by my long-term concerns but its helpful to see some serious studies demonstrating the surprising effectiveness of canvassing, at least in a situation like the youth vote in the 2002 Michigan mid-term. Come to think of it, the people that were yelling at me yesterday were all older middle-aged. Hmmm...