Background: Systematic reviews are likely to be most useful if they are conducted and reported at the highest possible quality, minimizing their susceptibility to bias. The QUOROM (QUality Of Reporting Of Meta-analyses) Statement was developed to help improve the quality of reports of systematic reviews.

Objectives: To revise the QUOROM Statement, specifically the original checklist, in the light of new evidence.

Methods: A three-day conference, involving approximately 30 methodologists, systematic reviewers, healthcare journal editors and a consumer, was held in Ottawa, Canada in June 2005. Prior to the meeting, participants were asked to review current checklist items and nominate others. The meeting included background presentations, including the results from a survey regarding the usefulness of the original checklist, and both small group and plenary sessions. Each item was reviewed in terms of its usefulness and evidence base. New items were also nominated for consideration. Following the conference the checklist underwent additional iterations through consultation with all participants and those invitees unable to attend the meeting.

Results: The revised QUOROM Statement consists of a 27-item checklist and four-part flow diagram. The checklist includes seven headings. There are several substantive revisions such as the addition of items concerning the use of a protocol and assessment of the risk of bias in included studies. There are also cosmetic changes, such as the addition of a column to number the checklist items. Participants also recommended the development of an explanatory and elaboration document. For each checklist item this document will present the item, provide an example of good reporting and its evidence base, and explain the rationale. A dissemination committee has been established to help implement the work of the QUOROM Group.

Conclusions: The revised QUOROM Statement is an up-to-date evidence-based approach for reporting systematic reviews.