Customers write book reviews for Amazon.com and rate stores at BizRate.com. Car drivers call up radio stations to report traffic jams or radar traps. In many cases individuals share their information to the benefit of an unknown group of recipients, even though doing so is costly for the...

We present a field experiment to assess the effect of own and peer wage variations on actual work effort of employees with hourly wages. Work effort neither reacts to an increase of the own wage, nor to a positive or negative peer comparison. This result seems at odds with numerous laboratory...