Games with a Purpose or Mechanised Labour? A Comparative Study

Mechanised labour and games with a purpose are the two most popular human computation genres, frequently employed to support research activities in fields as diverse as natural language processing, semantic web or databases. Research projects typically rely on either one or the other of these genres, and therefore there is a general lack of understanding of how these two genres compare and whether and how they could be used together to offset their respective weaknesses. This paper addresses these open questions. It first identifies the differences between the two genres, primarily in terms of cost, speed and result quality, based on existing studies in the literature. Secondly, it reports on a comparative study which involves performing the same task through both genres and comparing the results. The study's findings demonstrate that the two genres are highly complementary, which not only makes them suitable for different types of projects, but also opens new opportunities for building cross-genre human computation solutions that exploit the strengths of both genres simultaneously.