How is crowd work different? Traditional workplaces foster long-term relation - ships between workers and employers. Within these long-term relation ships, there is ample time for workers to be trained. By contrast, when crowds are assembled to do work, the relationship between employers and employees may only last as long as it takes to accomplish an individual task. While there is precedence for brief employment relationships in temporary work, day labour and piecework (Callaghan & Hartmann, 1991), crowd work allows substantially shorter engage - ments: many tasks hosted by sites such as Amazon’s Mechanical Turk (www. mturk.com/mturk/welcome) can be completed in minutes (Ipeirotis 2010).