Wikipedia is a web-based encyclopedia project written by volunteers. The vast majority of Wikipedia entries can be edited by any person with access to the Internet. Wikipedia is operated by the Wikimedia Foundation, a non-profit organisation.

Due to its open nature, critics have questioned Wikipedia's reliability and accuracy; specifically, concerns have been raised over susceptibility to vandalism and the addition of false or unverified information, uneven quality, systemic bias and inconsistencies, and the favouring of consensus over credentials in the Wikipedia editorial process. However, two scholarly studies have concluded that vandalism is generally short-lived and that Wikipedia is generally as accurate as other encyclopedias.

Even so, the Metagora policy on the use of Wikipedia as a source for its training materials is as follows:

• Wikipedia has been used as a source for an entry in the Encyclopedia of Terms when a qualified professional, that is, a person with extensive experience with and an advanced degree in the general topic of the encyclopedia entry, has reviewed the Wikipedia entry and determined the information to be valid and well-written.

• The Wikipedia entry has been modified from the original context to make it appropriate for use in the Metagora Encyclopedia of Terms.

• As the Wikipedia entry is continuously open to change, Metagora does not endorse the current version of the Wikipedia entry where it differs from the text given in the Metagora Encyclopedia of Terms.

• When possible, Metagora staff will strive to use additional or alternative sources of information to create entries in the Encyclopedia of Terms.

1. This definition is based on http://en.wikipedia.org/wiki/Wikipedia (accessed 7 June 2007).