Editorial and Publishing Policy Resource
Cochrane Database of Systematic Reviews (CDSR)

The Cochrane Database of Systematic Reviews (CDSR) is the leading resource for systematic reviews in health care. The CDSR includes Cochrane Reviews (the systematic reviews) and protocols for Cochrane Reviews as well as editorials. The CDSR also has occasional supplements.

In November 2004, The Cochrane Collaboration Steering Group agreed that the Cochrane Library should continue to be limited to the publication of Cochrane Reviews dealing with human health issues.

Cochrane Reviews and Protocols

Cochrane Reviews are systematic reviews of primary research in human health care and health policy, and are internationally recognised as the highest standard in evidence-based health care. They may either investigate the effects of interventions for prevention, treatment, and rehabilitation, or alternatively may assess the accuracy of a diagnostic test for a given condition in a specific patient group and setting. A unique feature of Cochrane Reviews is that they are living documents in that they are updated with new evidence that emerges. They were conceived as electronic publications from the outset, and designed to take advantage of features unique to electronic publishing.

Each systematic review addresses a clearly formulated question; for example: Can antibiotics help in alleviating the symptoms of a sore throat? All the existing primary research on a topic that meets certain pre-determined criteria is searched for and collated, and then assessed using stringent guidelines, to establish whether or not there is conclusive evidence about a specific treatment.

Each Cochrane Review is a peer reviewed systematic review that has been prepared by a team of authors and supported by a Cochrane Review Group editorial team in the Collaboration. Cochrane Reviews are prepared using Review Manager (RevMan) software provided by the Collaboration, and adhere to a structured methodological approach and format that is described in the Cochrane Handbook for Systematic Reviews of Interventions or Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Protocols for Cochrane Reviews are peer reviewed articles that describe the rationale for the review, the objectives, and the methods that will be used to locate, select, and critically appraise studies, and to collect and analyse data from the included studies.

There are four types of Cochrane Review published in the CDSR: intervention; methodology; diagnostic test accuracy; and overviews of reviews. Most reviews in the CDSR are intervention reviews, methodology reviews are prepared by one Cochrane Review Group, and the other two types are newer additions to the CDSR.

Editorials

Editorials aim to stimulate discussion and ideas around the development of evidence synthesis to promote good decision-making in clinical care and health policy.

One to four editorials are published each month. The timing of publication may coincide with the publication of a linked Cochrane Review or with particular events, such as health awareness days or The Cochrane Collaboration's 20th anniversary.

Editorials are usually about 800 words in length with about six to eight references, although longer or shorter editorials may be published at the discretion of the Editor in Chief, David Tovey (dtovey@cochrane.org).

Provenance

Editorials may be solicited or unsolicited, and authorship is not limited to contributors to The Cochrane Collaboration contributors or by those outside the organisation. The Editor in Chief or Cochrane Editorial Unit staff may commission editorials linked to Cochrane Reviews of interest or on topics likely to be of interest to a broad readership. Proposals for editorials are welcome and should be submitted to the Editor in Chief for consideration.

Editorial process

The Editor in Chief has editorial responsibility for editorials.  They are managed, edited, and published by the Cochrane Editorial Unit. Editorials can be published at any time.

Authors of editorials must declare potential conflicts of interest using the standard ICMJE Conflicts of interest form and must complete a licence for publication form.

Feedback on editorials is welcome and may be published as a comment alongside the editorial.

Editorials are indexed in PubMed and are free to access via the Cochrane Library homepage.

Supplements

Since 2009, the Cochrane Colloquium abstracts (for oral presentations and posters) have been published as a Supplement and, since 2010, Cochrane Methods (ISSN: 2044-4702), the official annual newsletter for methodological issues within The Cochrane Collaboration, has been published as an annual Supplement.

Editorial responsibility

Cochrane Reviews are prepared by Cochrane Review Groups, which are led by one or more Co-ordinating Editors. The Co-ordinating Editors are members of an Editorial Board. The Editor in Chief oversees the CDSR content. 

The Editor in Chief is responsible for the Editorials and oversees the preparation of the Supplements.

Metrics

Impact factor 

Each year in June, Thomson Reuters publish the impact factors of all journals indexed in the ISI Journal Citation Report. The Cochrane Database of Systematic Reviews (CDSR) impact factor describes the ratio of the number of Cochrane Reviews published, for example, during 2010 and 2011 to the number of citations these reviews received in 2012. The CDSR received its first impact factor in 2007.

Year Impact factor (IF) Downloads (where available)
2015 6.103 IF and usage report
2014 6.035 IF fact sheet | IF and usage report
2013 5.939 IF fact sheet | IF and usage report
2012 5.785 IF fact sheet | IF and usage report
2011 5.912 IF fact sheet | IF and usage report
2010 6.186 IF fact sheet | IF and usage report
2009 5.653 IF fact sheet | IF and usage report
2008 5.182 IF fact sheet | ––
2007 4.654
     

Individual Cochrane Review Groups receive impact factor reports and citation analysis reports prepared by the publishing team at Wiley. The publishing team at Wiley runs Impact Factor Webinars for Cochrane contributors. Contact Gavin Stewart, Associate Editor, Wiley, for more information; gstewart@wiley.com, +44 (0)1243 770 686.

The Cochrane Editorial Unit has compiled advice and information (January 2012) for Cochrane Review Groups about measures aimed at influencing the impact factor of the CDSR.

Article metrics

In 2011, Wiley introduced an article metric for each Cochrane Review. Users can now see which other articles have cited the Cochrane Review (via a live feed from CrossRef).

Wiley has also partnered with Altmetric, a service that tracks and measures the impact of scholarly articles and datasets on both traditional and social media. Altmetric scores and badges are displayed on Cochrane Reviews and Editorials published in the Cochrane Database of Systematic Reviews.

More information on Altmetric for CDSR

Features

MeSH terms

MeSH terms are sourced and added to reviews post-publication by Wiley. On an annual basis, Wiley downloads the MeSH thesaurus related files from from the National Library of Medicine (NLM) to build a new MeSH structure, which is introduced to the Cochrane Library.

Linking Cochrane Reviews to other related Cochrane Reviews

In 2011, Wiley introduced a ‘more content like this’ feature for Cochrane Reviews, which is built on the topics lists. At the bottom of each Cochrane Review, there is a hyperlink to the topics list heading under which the Cochrane Review is listed. Clicking on this hyperlink takes the user to that level of the topics list tree so that the user can view related reviews.

Browse options for Cochrane Reviews

Readers are given the option of browsing Cochrane Reviews through several different lists:

    • Browse list – as shown on the left-hand side of the Cochrane Library homepage (prepared by Cochrane – see below)
    • New Reviews
    • Updated Reviews
    • A–Z: all Protocols and Reviews
    • A–Z: by Cochrane Review Group
    • Topics by Cochrane Review Group (prepared by Cochrane – see below) Browse list

All of these are prepared automatically with the exception of the browse list on the homepage of the Cochrane Library and the topics lists.

The Cochrane Editorial Unit prepares the homepage ‘Browse by topics’ menu. This is a three-level browse menu for Cochrane Reviews only (excludes protocols) designed to present the scope of Cochrane Reviews across the landscape of medical specialties and broad healthcare topics, rather than being restricted to the way that coverage is defined by Review Groups. The aim is to helping users find relevant reviews. The Browse menu is populated automatically from the Cochrane Editorial Unit’s own topics list, which is maintained for this purpose. Cochrane Protocols are tagged appropriately in Archie, often based on the way that CRGs have assigned the review to their own topics lists, then appear automatically in the browse menu when the Review is published.

Cochrane Reviews from any Cochrane Review Group can be added to any of the three levels for the homepage browse list; for example, there are several Cochrane Review Groups working on cancer, and the reviews are brought together under the top-level ‘Cancer’ heading. This is in comparison with the topics lists in which the Cochrane Reviews are listed separately by Cochrane Review Group. A single Cochrane Review can be added to more than one heading; for example, oral cancers are located under the ‘Cancer’ top level heading and also ‘Dentistry and oral health’ top level heading. In addition, the browse menu offers top-level headings (e.g. Child health) that are built on Fields’ topics lists.

Each Cochrane Review Group prepares a topics list that covers the Group’s scope of work. The five-level topics list can include topics where reviews are in progress or completed, or topics where a review is desirable. In the former scenario, reviews are linked to the topic. The topics lists are updated each time a review is published and are listed under the ‘Topics by Cochrane Review Group’ browse option on the homepage. Some Fields also maintain topics lists.

Other content lists for Cochrane Reviews

A range of content lists are available for Cochrane Reviews: New Reviews; Updated Reviews; A–Z: all Protocols and Reviews; A–Z: by Cochrane Review Group. These are produced by the publisher using the data included in the XML ZIP file for Cochrane Reviews and are prepared as part of the production process for the Cochrane Reviews.

Access to archived Cochrane Reviews

All published versions of Cochrane Reviews (including Protocols for Cochrane Reviews) are stored on The Cochrane Collaboration’s central server, Archie. This also includes versions published before the launch of Archie in 2005–2006. The published versions stored in Archie cannot be deleted. Archie also contains versions of draft Cochrane Reviews that are not published.

Full access to the archive of all published Cochrane Reviews in Archie is available only to a few individuals in each Cochrane entity, such as Cochrane Review Groups (CRGs), as well as Archie Super Users and system and data administrators. This access to the archive can help CRG editorial teams answer queries about previously published versions that are not available in the public archive through the Cochrane Database of Systematic Reviews (CDSR) (see below). However, it is at the discretion of the CRG editorial teams as to whether they choose to provide copies of Cochrane Reviews to people who have asked for them.

Researchers who are proposing to use the archived data for methodological purposes can also apply for permission for access to all previously published reviews by contacting Jessica Thomas (jthomas@cochrane.org), Business and Operations Manager at the Cochrane Informatics and Knowledge Management Department (IKMD). A framework for evaluating such requests is being developed. If permission is granted, the IKMD can assist in providing these data, but there may be a cost for this service depending on the complexity of the request.

The CDSR includes an archive of all citation versions of published Cochrane Reviews (including Protocols) starting from Issue 4, 2003 (www.cochranelibrary.com). Where previous versions of a Cochrane Review exist in the CDSR, these can be accessed via the ‘Other Versions’ link on each Cochrane Review. 

Section info
Describe change
2015 Impact Factor and usage report added
Change date
9 September 2016