Cochrane Eyes and Vision Group
Guidelines for peer reviewers of reviews
Introduction
These guidelines have been prepared for people who have agreed to provide peer review comments on a systematic review being prepared within the Cochrane Eyes and Vision Group.
What is the Cochrane Eyes and Vision Group?
The Cochrane Eyes and Vision Group is part of the international Cochrane Collaboration. The Group aims to prepare high quality systematic reviews on the effects of interventions used to prevent or treat eye diseases or visual impairment. The editorial base for the group, located at the London School of Hygiene & Tropical Medicine in London, co-ordinates and supports the preparation of systematic reviews by authors all over the world. These high quality reviews are published on The Cochrane Library, an electronic journal published quarterly on CD-ROM and on the Internet that contains a number of databases relevant to evidence based medicine. You can find out more about the Collaboration at www.cochrane.org and about the Eyes and Vision Group at http://www.cochraneeyes.org.
What are Cochrane systematic reviews?
Cochrane reviews use systematic methods to locate, appraise and summarise evidence from controlled trials regarding the effectiveness of health care interventions. The reviews are contained in structured reports that are published on the Cochrane Database of Systematic Reviews on The Cochrane Library. The first step of the review process is to prepare a protocol for the review. The protocol describes 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. The protocol is published, and then the complete review is carried out according to the protocol.
What is the purpose of peer review?
All Cochrane protocols and reviews are reviewed by peer reviewers prior to publication. Peer reviewers are people with relevant content, methodological or user expertise, who critically examine reviews in their area of expertise. Peer reviewers’ comments are forwarded to the review author so that the review can be amended where necessary, before it is sent for publication.
How to return your comments
The remainder of this document gives more detailed information about the information that should be included in each section of a Cochrane review. We ask you to refer to this while reviewing the review. You are welcome to comment on any aspect of the review, but we are particularly interested in your comments on the scope and content of the review and seek your opinion on: • whether the conclusions of the review are in keeping with the results presented • whether you are aware of any other trials (published, unpublished or ongoing) that would be relevant to the review We would be grateful if you could separate your comments into general comments (that do not require any changes to be made) and specific comments for changes to the review that are required or suggested. It would also be helpful if you could number these into separate points. Please return your comments in an e-mail to Anupa (cevg@lshtm.ac.uk) or by post/fax to Anupa Shah, International Centre for Eye Health, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK. Fax +44 (0)20 7958 8325.
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Guidelines for peer reviewers of reviews cont.
GUIDE TO THE FORMAT OF A COCHRANE REVIEW Cover sheet
The cover sheet includes general information about the review including: Title: The title should succinctly state the focus of the review. It should make clear the intervention(s) reviewed and the problem at which the intervention is directed. Date edited: The date the review was last changed Contact author: This should be the contact details for the person to whom correspondence about the review should be addressed. Co-authors: This should contain the contact details for any co-authors on the review. Contributions: The names and contribution of all individuals who have contributed to a Cochrane Review should be described in this section. One contributor should be identified as the guarantor of the review. List of authors for citation: This can be considered the ‘byline’ for Cochrane reviews. Sources of support to the review: Review author should give details of grants that supported the review and other forms of support, such as support from their university or institution in the form of a salary. Issue protocol first published: The issue of The Cochrane Library where the protocol will be first published.
Synopsis/ Plain language summary
The synopsis is a brief summary of the results of the review in plain language for consumers and nonspecialist readers. The synopsis does not replace the abstract but is an additional product. It will be published as part of the Cochrane Review in the Cochrane Database of Systematic Reviews. Sentences should be short and use the most easily understandable language possible. The text should briefly cover: the context and alternatives relating to the problem and interventions; the potential benefits and risks of the interventions; and the main findings of the review.
Abstract
All full reviews must include an abstract of not more than 400 words. It should be kept as brief as possible without sacrificing important content. Abstracts are made freely accessible on the Internet and will often be read as stand-alone documents. They should, therefore, summarise the key methods and content of the review and not contain any material that is not in the review. The content must be consistent with the text, data and conclusions of the review and not include references to any information outside the abstract.
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Text of the review
The text of the review should be as succinct as possible. It should be written so that someone who is not an expert in the area can understand it. The readability of Cochrane Reviews should be comparable to that of a well-written article in a general medical journal. Background: The review should begin with a brief synthesis of the underlying biology and healthcare of the topic being reviewed. This background should make clear the motivation and rationale for the review. It should be presented in a fashion that is understandable to the consumers of that healthcare. Objectives: This should begin with a precise statement of the primary objective of the review, including the intervention(s) reviewed and the targeted problem. It might also mention why this review was undertaken and how it might relate to a wider review of a general problem. Criteria for considering studies for this review: The criteria used to select studies for inclusion in the review should be stated. Types of studies (e.g. ‘all randomised controlled comparisons’ or ‘all double blind randomised controlled trials’), types of participants, types of interventions and types of outcome measures are subheadings in this section. Search strategy for identification of studies: The data sources used to identify studies should be summarised, including bibliographic databases, reference lists from pertinent articles and books, conference proceedings and personal contact with experts or organisations active in the area. Methods of the review: This should include the method used to apply the selection criteria (e.g. if they were applied independently by more than one author), the criteria used to assess the quality of studies and how they were applied, how data were obtained (e.g. if individual patient data were sought, or if the number of events was calculated from published survival curves), how the data were synthesised, and any statistical techniques used and sensitivity analyses performed. Description of studies: This should refer to the information contained in the ‘Characteristics of Included Studies’ and the ‘Characteristics of Excluded Studies’ tables. It should describe key characteristics of the study participants, interventions and outcome measures in the included studies and any important differences among the studies. Methodological quality of included studies: This should describe the general quality of the included studies and any important flaws in individual studies. If the quality of each study was assessed using explicit criteria, the criteria that were used should be described or referenced under ‘Methods’. Results: This should be a summary of the main findings of the review and any sensitivity analyses that were undertaken. Subheadings can be used if they make reading easier (e.g. for each prior hypothesis if a review addresses more than one). The results of individual trials, and any statistical summary of these, should be included in Data tables. Discussion: This should include brief comments on any methodological limitations of the included studies and the review that are important for decisions about practice or future research. Comments on how the included studies fit into the context of other evidence might be included here, stating clearly whether the other evidence was systematically reviewed. Comments on how the results of the review fit into the context of current clinical practice might be included here, although it should be kept in mind that current clinical practice might vary internationally.
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Guidelines for peer reviewers of reviews cont.
Authors’ conclusions: The primary purpose of the review should be to present information, rather than to offer advice. Implications for practice and Implications for research are subheadings in this section. The implications for practice should be as practical and unambiguous as possible. They should not go beyond the evidence that was reviewed. ‘No evidence of effect’ should not be confused with ‘evidence of no effect’. The implications for research should not include vague statements such as ‘more research is needed’. It should state exactly what research is needed, why and how urgently. Opinions on how the review might be improved with additional data or resources might also be included here. Acknowledgements: This section should be used to acknowledge any individuals or organisations who the author wish to acknowledge but who have not made a sufficient contribution to the review to be included in the Contributions section. Conflict of interest Any conflict of interest capable of influencing the judgements of any of the authors should be reported, including financial, personal, political or academic conflicts. If there are no conflicts of interest, this should be stated explicitly, e.g. by reporting ‘None known’.
References
References to studies are organised under four standard headings: included studies, excluded studies, studies awaiting assessment, and ongoing studies. Other references include additional references that are cited in the review and other published versions of the review; e.g. if the review has been published in a journal.
Tables and figures
Characteristics of included studies: This is a standard table with seven columns: study ID, methods, participants, interventions, outcomes, notes and allocation concealment. Authors must decide what characteristics of the included studies are likely to interest users of the review. It is possible to use codes so that each column can include several subcategories of information; e.g. an author could include country, setting and sex under ‘participants’. Information on the funding of a study could be included under ‘notes’. Characteristics of excluded studies: Any studies meeting the inclusion criteria, or appearing to meet the inclusion criteria, that were excluded should be identified and the reason for exclusion should be given (e.g. inappropriate control group). Characteristics of ongoing studies: This is a standard table with seven columns: Study ID, Trial name or title, Participants, Interventions, Outcomes, Starting date, Contact information and Notes. Comparisons and data: A review can include more than one comparison and a study can be included in more than one of these. The comparisons should correspond to the questions or hypotheses under ‘Objectives’. Tables and figures for each comparison are generated from the data.
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