Let them say what's on their minds

I know I must have brought this up before, but I still think it's a good idea to let people leave comments about conference sessions and speakers on the meeting's Web site, in addition to just the evaluation. And now there's some proof in the form of a paper called “The Availability Heuristic in the Classroom: How Soliciting More Criticism Can Boost Your Course Ratings” by Craig R. Fox, UCLA Anderson School and Department of Psychology (link goes to Guy Kawasaki's blog, where you can download the paper as a pdf). Guy says:

In this study, two groups of students filled out an evaluation of an MBA course. One group was asked for two ways to improve the course; the other was asked for ten ways to improve the course. The group that was asked to list ten ways showed a higher level of satisfaction with the course. My interpretation is that the more you enable people to provide feedback and comments, the higher they might evaluate your product or service—simply because you asked for feedback and comments.

Go ahead and ask them for more input and see what happens. I'd be curious to know how this plays out in a conference setting, as opposed to a university course, but I'm guessing the end result might be similar.