Bargaining in Legislatures: An Experimental Investigation of Open Versus Closed Amendment Rules

Abstract

We investigate the Baron-Ferejohn (1989a) bargaining model of legislative behavior comparing open versus closed amendment rules. The data are qualitatively consistent with the theory as there are longer delays in distributing benefits and a more egalitarian distribution of benefits under the open amendment rule, the proposer gets a larger share of the benefits than coalition members under both rules, and play converges towards minimal winning coalitions under the closed amendment rule. However, there are important quantitative differences between the theory and data as the frequency of minimal winning coalitions is much greater under the closed rule (the theory predicts minimal winning coalitions under both rules for our parameter values) and the distribution of benefits between coalition members is much more egalitarian than predicted. The latter are consistent with findings from shrinking pie bilateral bargaining game experiments in economics, which we relate our results to.