I thought anyone going to conference who wondered how the debates at it work, might be interested in this post I wrote just after conference last year, outlining how debates get structured and how speakers are selected for them. Many people do seem to believe that whether or not you get called depends mostly on whether in the bar last night you were rude to the person chairing the session - so it may still be a surprise to some to see that it is in fact somewhat more scientific than that!