Feedback and Timing in a Crowdsourcing Game
  The present research examines two problems inherent to the creation of crowdsourcing games: how to give feedback when the right answer is not always known by the game and how much time to give players without sacrificing data quality. Taken together, the present research provides an important first step in considering how to create fun, challenging crowdsourcing games that generate quality data. 
Gili Freedman, Sukdith Punjasthitkul, Max Seidman, and Mary Flanagan
cs.HC