Quick Quizzes

John Piazza brings up a whole can of worms question:
I have recently received some criticism for, and heard from others who have stopped using, the true/false quick quizzes. The argument against them is that because students can guess, they are not accurate indicators of student knowledge/acquisition/progress. Over the past 3 years of using them, however, I have found them to be very accurate formative assessments, and pretty fairly reflect whether or not a student (or entire class) is “getting it.” I am wondering if there is any research out there that I can refer to if/when I come under attack for using these, or in order to encourage colleagues to use them.
Thanks,
John