If you’re in D.C., you should stop by. . . . I’m speaking in the statistics department at George Washington University on the topic of interactions. Here’s the powerpoint and here’s the abstract:

As statisticians and practitioners, we all know about interactions but we tend to think of them as an afterthought. We argue here that interactions are fundamental to statistical models. We first consider treatment interactions in before-after studies, then more general interactions in regressions and multilevel models. Using several examples from our own applied research, we demonstrate the effectiveness of routinely including interactions in regression models. We also discuss some of the challenges and open problems involved in setting up models for interactions.

The talk will be today, Wed 10 Sept, at 3pm, I think. I don’t yet know the room but you can call the department (202-994-6356) and they should be able to give you directions.

Tomorrow (Thurs) I’ll be speaking with Boris at noon at the Cato Institute on Red State, Blue State. It’s not too late to sign up for that.