In a service setting, the output of piece work can be measured by the number of operations completed, as when a telemarketer is paid by the number of calls made or completed, regardless of the outcome of the calls (pay for only certain positive outcomes is more likely to be called a sales commission or incentive pay). Crowdsourcing systems such as Mechanical Turk involve minute information-processing tasks (such as identifying photos or recognizing signatures) for which workers are compensated on a per-task basis.