Crowdsourced Fact Validation for Knowledge Bases

In spite of its wide usage in various applications, existing construction methods for Knowledge Base (KB) are still on their way to obtaining 100% correct facts. Thus, employing crowd workers to validate a KB has been proposed to improve its reliability. Most of the existing works focus on devising games with proper incentives to engage workers in validating more facts, but rarely consider matching facts with proper workers. Facts have diverse domains (topics), which naturally require workers of different expertise. In addition, they also generally have different utilities, i.e., some are more heavily used than others. Thus, distinguishing the facts in terms of utility to give them different validation priorities is meaningful, especially when the budget is limited. To this end, we study the crowdsourced fact validation problem which considers worker domains and fact utilities, and find that with some reductions, it can be solved by the existing minimum cost network flow method. However, directly employing that method requires a huge time cost. We thereby propose an optimized network flow method which reduces the network complexity to save the time cost by properly grouping the facts. Furthermore, we propose an incremental validation method, which utilizes the previous results for validating an evolving KB. We finally conduct extensive experiments to demonstrate the effectiveness of the proposed methods.