Using a gift-exchange experiment, we show that the ability of reciprocity to overcome incentive problems inherent in principalâagent settings is greatly reduced when the agentâs effort is distorted by random shocks and transmitted imperfectly to the principal. Specifically, we find that gift exchange contracts without shocks encourage effort and wages well above standard predictions. However, the introduction of random shocks reduces wages and effort, regardless of whether the shocks can be observed by the principal. Moreover, the introduction of shocks significantly reduces the probability of fulfilling the contract by the agent, the payoff of the principal, and total welfare. Therefore, our findings demonstrate that random shocks place an important bound on the ability of gift exchange to overcome principalâagent problems. Data, as supplemental material, are available at http://dx.doi.org/10.1287/mnsc.2015.2177 . This paper was accepted by John List, behavioral economics.