Guardian Unlimited came top and Sky News bottom in a study of media transparency and openness that has itself been criticised for methodological errors.

The International Center for Media and the Public Agenda (ICMPA) at University of Maryland assessed 25 international news websites on their corrections policy, communication of their corporate make-up, openness on internal staff policies, its reporting and editing policies, as well as its readiness to take readers' comments and criticisms.

Guardian Unlimited beat The New York Times to the top slot but was marked down on interactivity, despite operating the Commentisfree weblog portal and several other thematic blogs.

In twelfth place, Telegraph.co.uk was rated "poor" for lacking a corrections page, having a "vague" of code of ethics and lacking an ombudsman or a policy on news values.

ITN, which tied with Al-Jazeera English at 14, was branded "not acceptable" after failing on all counts except provision of information about its ownership.

Sky News ranked worst of all for not having a corrections page, having a poor corporation ownership statement and lacking policies required by the study. However, it was not made clear whether it surveyed the site before or after its mid-April redesign, which aimed to increase reader participation.

Some have suggested that the ICMPA's study is seriously flawed. Former technology editor at BBC News, Alfred Hermida, wrote on Wednesday: "I was surprised by the results, until I realised that the study had looked at the BBC World Service site, rather than the actual BBC News website.

"It is hard to understand how the authors of the study could have considered the World Service site as the main BBC global news site. This is a fundamental error in methodology. This basic mistake seriously undermines the credibility of its findings."

At time of writing, the survey findings were updated to refer to the correct website, ranked it third and cited its Editors' Blog as indicative of openness, however.

Sky News alum Simon Dickson responded to the site's bottom placing: "It’s not down to any kind of unwillingness on the part of the team, or any secretive activity.

"It’s a tiny team, something like a dozen staff compared to the hundreds at their rivals, trying to do a full-scale news production effort with (until very recently) little credibility among the 'proper' production staff on the TV side."

An ICMPA report last month chastised 19 online news publishers for failing to use their RSS feeds properly. This most recent study comes at a time when calls have been made, particularly in the US, for greater transparency in news and politics.

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