Static and Dynamic Underinvestment: An Experimental Investigation

In this paper we design a stylized version of an environment with public goods, dynamic linkages, and legislative bargaining.  Our theoretical framework studies the provision of a durable public good as a modified version of Battaglini et al. (2012).  We develop an experimental design that allows us to disentangle inefficiences that would result in a one-shot world (static inefficiencies) from extra inefficiencies that emerge in an environment in which decisions in the present affect the future (dynamic inefficiencies).  We solve for efficiency and also characterize the bargaining equilibrium, a symmetric stationary subgame-perfect equilibrium, which is the most common concept used in applied work.  The experimental results indicate that subjects do react to dynamic linkages and, as such, we find evidence of both static and dynamic inefficiencies.  In fact, the quantitative predictions of the model with respect to the share of dynamic inefficiencies are closest to the data which dynamic linkages are high.  To the extent that behavior is different from what is predicted by the model, a systematic pattern emerges, namely the use of strategic cooperation whereby subjects increase the efficiency of period one propoals by selectively punishing, in period two, subjects who did not propose efficient allocations.