Intertemporal coordination in volunteer markets

Many volunteer markets, and most prominently markets for substances of human origin, feature dynamic coordination problems where volunteering today can temporarily restrict volunteering later. We show that, unsurprisingly, these restrictions reduce market surplus compared to no restrictions. We examine whether providing volunteers with demand or supply information improves market surplus without and with intertemporal restrictions. We show theoretically that, without restrictions, providing demand or supply information increases market surplus, while with restrictions, providing supply rather than demand information causes higher market surplus. Experimental results support most predictions and further show that supply information especially improves market surplus when intertemporal restrictions exist. Overall, comparative static inferences in an environment without intertemporal restrictions do not carry over to an environment with restrictions. Thus, policies based on analyses of static conditions will not necessarily be effective in situations featuring dynamic spillovers.