Opt in vs. Opt out

Last fall I used the Piazza discussion forums to let students ask questions and get answers outside of class. It was a huge success and this term I looked forward to more of the same. Strangely, however, I noticed participation in the forums has been much lower this year. As of the end of the fifth week of classes, students have posted just 47 questions compared to 77 questions posted at this point last year. What’s changed?

While it’s true that this year’s class has 15% fewer students (127 vs 150), that isn’t enough to explain a 39% drop. I think the real culprit is that last year students were automatically enrolled in Piazza at the beginning of the semester, and this year students have had to make a small but conscious effort to sign up. Once enrolled, students get email notifications when new questions are posted, and I think this encourages participation. The economics literature is full of examples where a nudge toward participation can make a big difference in behavior–contribution to retirement savings programs is the canonical example.

As of midnight last night, 72 of my 127 students were enrolled in Piazza. This morning I manually enrolled the other 55. They can turn off their email notifications or even unenroll with very little effort, but I suspect most will find the system pretty useful, especially before exams and before problem sets are due. Maybe they just needed a little nudge.