Wikipedia contributors who wish to call attention to their credentials in their role as editors of the online encyclopedia might have to back their claims with evidence after an editor was exposed as a fraud last week.

The online reference website suffered a blow to its reputation after it was revealed an editor who had represented himself as a university professor was in fact a 24-year-old from Kentucky named Ryan Jordan with no higher-education credentials.

Jordan, who went by the name EssJay, told the New Yorker magazine last year he was a tenured professor of religion at a private university with "a PhD in theology and a degree in canon law." But Jordan was exposed after he accepted a job at Wikia, the Internet company run by Wikipedia founder Jimmy Wales.

Wales initially backed Jordan but has since asked for his resignation and has removed him from the Wikipedia website.

"I have asked EssJay to resign his positions of trust within the community," Wales wrote on Wikipedia's website. "From the moment this whole thing became known, EssJay has been contrite and apologetic."

Wales said the site would consider requiring editors who wish to represent themselves as experts in a particular field to provide evidence to back it up, but said editors should not be required to have expertise in order to make changes to a particular entry.

"Wikipedia is built on (among other things) twin pillars of trust and tolerance. The integrity of the project depends on the core community being passionate about quality and integrity, so that we can trust each other. The harmony of our work depends on human understanding and forgiveness of errors."

Wikipedia has come under fire for its volunteer editing policy, which allows users to post, edit and delete items, a process critics argue exposes entries to vandalism.

Golfer sues

In the most recent case involving vandalism on the website, pro golfer Fuzzy Zoeller launched a lawsuit against the owner of an internet address last month in an effort to track down the author of what he considered a defamatory paragraph about him on Wikipedia.

The lawsuit said the entry alleged Zoeller abused drugs, alcohol and his family with no evidence to back up the statements. Wikipedia editors have since taken down the derogatory information.

Wikipedia critic Daniel Brandt blasted the site last year when he pointed out 142 passages that had been plagiarized.

But despite the scandals, Wikipedia's popularity continues to grow, and some researchers have suggested the practice of community editing leads to improved accuracy.

A study published on Cornell University's arXiv website last week found that stories edited more frequently were also the most accurate.

The researchers looked at 1,211 featured articles — those deemed by users to be particularly useful — and found on average they had more edits and contributors than entries deemed less accurate or thorough on the site.

"Wikipedia article quality continues to increase, on average, as the number of collaborators and the number of edits increases," said the report by Dennis Wilkinson and Bernardo Huberman from the Hewlett Packard Information Dynamics Laboratory in Palo Alto, Calif.