Provision of Step-Level Public Goods with Uncertain Provision Threshold and Continuous Contribution

Common to most theoretical and empirical research on public goods is the assumption that the parameters of the game are common knowledge. Recent theoretical and empirical studies have questioned this assumption by arguing that many public goods situations are characterized by uncertainty regarding various aspects of the situation. In particular, Suleiman (1997) argued that members of production groups of step-level public goods are often uncertain about the value of the provision threshold. For this type of uncertainty he proposed three distinct models to account for the individual's contribution. The present study reports the results of an experiment designed primarily to test and contrast the predictions derived from two of these models - a subjective expected utility model and a cooperative model-regarding the effects of threshold uncertainty on contribution for the provision of step-level public goods. Other goals of the study were to test the joint effect of the threshold uncertainty level, and its mean (low vs. high), on contribution, and to examine the effect of threshold uncertainty on the individuals' estimates regarding the contributions of other group members. The results show that the effect of threshold uncertainty is moderated by the threshold mean: Contribution to the public good increased as a function of uncertainty for the lower threshold mean, and decreased (though not significantly) for the higher threshold mean. In contrast, for the two threshold means the subjects' estimates of the mean and variability of others' contribution increased with threshold uncertainty. The models' comparison revealed that the cooperative model was superior to the subjective expected utility model. This result adds to a substantial body of research on social dilemmas showing that under conditions of social (strategic) uncertainty, group members tacitly coordinate their choice behavior by anchoring their decisions on rules of fairness.