Incentives in Experiments: A Theoretical Analysis

Abstract

Experimental economists currently lack a convention for how to pay subjects in experiments with multiple tasks. We provide a theoretical framework for analyzing this question. Assuming monotonicity (dominated gambles are never chosen) and nothing else, we prove that paying for one randomly-chosen problem — the random problem selection (RPS) mechanism — is essentially the only incentive compatible mechanism. Paying for every period is similarly justified when we assume only a ‘no complementarities at the top’ (NCaT) condition. To help experimenters decide which is appropriate for their particular experiment, we also discuss empirical tests of these two assumptions.