IMDEA Networks Institute Publications Repository

The Importance of Being Earnest in Crowdsourcing Systems

Tarable, Alberto and Nordio, Alessandro and Leonardi, Emilio and Ajmone Marsan, Marco (2015) The Importance of Being Earnest in Crowdsourcing Systems. In: The 34th IEEE International Conference on Computer Communications (IEEE INFOCOM 2015), 26 April - 1 May 2015, Hong Kong, China.

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This paper presents the first systematic investigation of the potential performance gains for crowdsourcing systems deriving from available information at the requester about individual worker earnestness (reputation). In particular, we first formalize the optimal task assignment problem when workers' reputation estimates are available, as the maximization of a monotone (submodular) function subject to Matroid constraints. Then, being the optimal problem NP-hard, we propose a simple but efficient greedy heuristic task allocation algorithm. We also propose a simple "maximum a posteriori" decision rule. Finally, we test and compare different solutions, showing that system performance can greatly benefit from information about workers' reputation. Our main findings are that: i) even largely inaccurate estimates of workers' reputation can be effectively exploited in the task assignment to greatly improve system performance; ii) the performance of the maximum a-posteriori decision rule quickly degrades as worker reputation estimates become inaccurate; iii) when workers' reputation estimates are significantly inaccurate, the best performance may be obtained by combining our proposed task assignment algorithm with the decision rule introduced in [1,2].

Item Type: Conference or Workshop Papers (Paper)
Depositing User: Rebeca De Miguel
Date Deposited: 03 Dec 2014 14:12
Last Modified: 13 Jan 2015 13:35

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