Wikidata, like Wikipedia, is a knowledge base that anyone can edit. This open collaboration model is powerful in that it reduces barriers to participation and allows a large number of people to contribute. However, it exposes the knowledge base to the risk of vandalism and low-quality contributions. In this work, we build on past work detecting vandalism in Wikipedia to detect vandalism in Wikidata. This work is novel in that identifying damaging changes in a structured knowledge-base requires substantially different feature engineering work than in a text-based wiki like Wikipedia. We also discuss the utility of these classifiers for reducing the overall workload of vandalism patrollers in Wikidata. We describe a machine classification strategy that is able to catch 89 of vandalism while reducing patrollers' workload by 98 , by drawing lightly from contextual features of an edit and heavily from the characteristics of the user making the edit.
Wikipedia's success is often attributed to the large numbers of contributors who improve the accuracy, completeness and clarity of articles while reducing bias. However, because of the coordination needed to write an article collaboratively, adding contributors is costly. We examined how the number of editors in Wikipedia and the coordination methods they use affect article quality. We distinguish between explicit coordination, in which editors plan the article through communication, and implicit coordination, in which a subset of editors structure the work by doing the majority of it. Adding more editors to an article improved article quality only when they used appropriate coordination techniques and was harmful when they did not. Implicit coordination through concentrating the work was more helpful when many editors contributed, but explicit coordination through communication was not. Both types of coordination improved quality more when an article was in a formative stage. These results demonstrate the critical importance of coordination in effectively harnessing the "wisdom of the crowd" in online production environments. Wikipedia needs to attract and retain newcomers while also increasing the quality of its content. Yet new Wikipedia users are disproportionately affected by the quality assurance mechanisms designed to thwart spammers and promoters. English Wikipedia's Articles for Creation provides a protected space for drafting new articles, which are reviewed against minimum quality guidelines before they are published. In this study we explore how this drafting process has affected the productivity of newcomers in Wikipedia. Using a mixed qualitative and quantitative approach, we show how the process's pre-publication review, which is intended to improve the success of newcomers, in fact decreases newcomer productivity in English Wikipedia and offer recommendations for system designers. The success of Wikipedia and the relative high quality of its articles seem to contradict conventional wisdom. Recent studies have begun shedding light on the processes contributing to Wikipedia's success, highlighting the role of coordination and contribution inequality. In this study, we expand on these works in two ways. First, we make a distinction between global (Wikipedia-wide) and local (article-specific) inequality and investigate both constructs. Second, we explore both direct and indirect effects of these inequalities, exposing the intricate relationships between global inequality, local inequality, coordination, and article quality. We tested our hypotheses on a sample of a Wikipedia articles using structural equation modeling and found that global inequality exerts significant positive impact on article quality, while the effect of local inequality is indirect and is mediated by coordination