An Experimental Study of Vote Trading

Vote trading is believed to be ubiquitous in committees and legislatures, and yet we know very little of its properties. We return to this old question with a laboratory experiment. We posit that pairs of voters exchange votes whenever doing so is mutually advantageous. This generates trading dynamics that always converge to stable vote allocations--allocations where no further improving trades exist. The data show that stability has predictive power: vote allocations in the lab converge towards stable allocations, and individual vote holdings at the end of trading are in line with theoretical predictions. However, there is only weak support for the dynamic trading process itself