Identifying Duplicate and Contradictory Information in Wikipedia

In this paper, we identify sentences in Wikipedia articles that are either identical or highly similar by applying techniques for near-duplicate detection of web pages. This is accomplished with a MapReduce implementation of minhash to identify sentences with high Jaccard similarity, followed by a pass to generate sentence clusters. Based on manual examination, we discovered that these clusters can be categorized into six different types: templates, identical sentences, copyediting, factual drift, references, and other. Two of these categories are particularly interesting: identical sentences quantify the extent to which content in Wikipedia is copied and pasted, and near-duplicate sentences that state contradictory facts point to quality issues in Wikipedia.