B.T. Adler, J. Benterou, K. Chatterjee, L. de Alfaro, I. Pye, V. Raman. Assigning Trust To Wikipedia Content. Technical Report UCSC-CRL-07-09, School of Engineering, University of California, Santa Cruz, CA, USA. November 2007. Abstract PDF


The Wikipedia is a collaborative encyclopedia: anyone can contribute to its articles simply by clicking on an ``edit'' button. The open nature of the Wikipedia has been key to its success, but has also created a challenge: how can readers form an informed opinion on its reliability? We propose a system that computes quantitative values of trust for the text in Wikipedia articles; these trust values provide an indication of text reliability.

The system uses as input the revision history of each article, as well as information about the reputation of the contributing authors, as provided by a reputation system. The trust of a word in an article is computed on the basis of the reputation of the original author of the word, as well as the reputation of all authors who edited the text in proximity of the word. The algorithm computes word trust values that vary smoothly across the text; the trust values can be visualized using varying text-background colors. The algorithm ensures that all changes to an article text are reflected in the trust values, preventing surreptitious content changes.

We have implemented the proposed system, and we have used it to compute and display the trust of the text of thousands of articles of the English Wikipedia. To validate our trust-computation algorithms, we show that text labeled as low-trust has a significantly higher probability of being edited in the future than text labeled as high-trust. Anecdotal evidence seems to corroborate this validation: in practice, readers find the trust information valuable.