PURPOSE:

A wiki is a collaborative Web site, such as Wikipedia, that can be freely edited. Because of a wiki's lack of formal editorial control, we hypothesized that the content would be less complete and accurate than that of a professional peer-reviewed Web site. In this study, the coverage, accuracy, and readability of cancer information on Wikipedia were compared with those of the patient-orientated National Cancer Institute's Physician Data Query (PDQ) comprehensive cancer database.

METHODS:

For each of 10 cancer types, medically trained personnel scored PDQ and Wikipedia articles for accuracy and presentation of controversies by using an appraisal form. Reliability was assessed by using interobserver variability and test-retest reproducibility. Readability was calculated from word and sentence length.

RESULTS:

Evaluators were able to rapidly assess articles (18 minutes/article), with a test-retest reliability of 0.71 and interobserver variability of 0.53. For both Web sites, inaccuracies were rare, less than 2% of information examined. PDQ was significantly more readable than Wikipedia: Flesch-Kincaid grade level 9.6 versus 14.1. There was no difference in depth of coverage between PDQ and Wikipedia (29.9, 34.2, respectively; maximum possible score 72). Controversial aspects of cancer care were relatively poorly discussed in both resources (2.9 and 6.1 for PDQ and Wikipedia, respectively, NS; maximum possible score 18). A planned subanalysis comparing common and uncommon cancers demonstrated no difference.

CONCLUSION:

Although the wiki resource had similar accuracy and depth as the professionally edited database, it was significantly less readable. Further research is required to assess how this influences patients' understanding and retention.