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Systematic Map


Systematic Maps are overviews of the distribution and abundance of evidence in relation to multifaceted elements of a broad question of policy or management relevance. The process and rigour of the mapping exercise is the same as for systematic review except that no evidence synthesis is attempted to seek an answer to the question. Some critical appraisal of the quality of the evidence is encouraged but may be limited when the quantity of articles is very large (and even absent in some circumstances). Authors should note that all Systematic Maps published in Environmental Evidence will have been conducted according to the CEE process. Full guidelines and standards can be accessed here (a quick guide to the publication process is available in Section 1.1).

Note that Environmental Evidence expects all submitting authors to complete the relevant ROSES form as part of their submission to demonstrate that they have reported all relevant methodological details. Authors should also use the ROSES template for a flow diagram to report on the screening process. Templates for ROSES forms can be accessed here and the flow diagram here. ROSES forms and the flow diagram should always be downloaded from the ROSES website as it contains most up-to-date templates. Please note the formatting of your submission should follow journal guidelines and not the ROSES template. The ROSES forms should be uploaded along with the submitted manuscript as a single-page supplementary file in a PDF format. Failure to do so could result in your manuscript being returned before review. In order to convert your completed ROSES form from a spreadsheet to a single-page PDF document, please scale the ROSES sheet to fit A4 landscape size.

For Systematic Maps to be relevant to policy and practice they need to be as up-to-date as possible. Consequently, at the time of submission for publication, the search should normally be less than one year old and a maximum of two years old. We will consider publication of updates of existing systematic maps, typically from three years since the original search, but earlier if the development of the evidence base justifies the update.

Systematic maps should normally be no longer than 20000 words (including references but excluding appendices and additional files).

Preparing your manuscript

Please note that your manuscript must include a 'Declarations' section including all of the subheadings (please see below for more information).

Title page

This should list the title of the article. The title should express the review findings and indicate that it is a systematic map, for example:

  • Existing evidence on the effectiveness of intervention A in on subject B? A systematic map.
  • Existing evidence on the impact of factor X on subject Y? A systematic map.

The full names, institutional addresses, and email addresses for all authors must be included on the title page. The corresponding author should also be indicated.


The Abstract of the manuscript should not exceed 500 words and must be structured into the following separate sections: Background, the context and purpose of the review, including the review question; Methods, how the review was performed including brief overview of all methodological steps; Review findings, the main findings, including results of search and assessment of evidence base; Conclusions, brief summary and potential implications for policy/management and research.


Three to ten keywords representing the main content of the article should be given. Please avoid repeating words that are already in the title.


The Background section should be written in a way that is accessible to readers without specialist knowledge in that area and must clearly state - and, if helpful, illustrate - the background to the review and its aims. Reports should indicate why this study was necessary and what it aimed to contribute to the field. A theory of change and/or conceptual model should be presented that links the intervention or exposure to the outcome. The role of commissioners and other stakeholders in the formulation of the question should be described and explained. The section should end with a brief statement of what is being reported in the article. A clear reference should be made to the protocol and any differences between what was planned and what was conducted.

Objective of the Review

This section should describe the primary question and secondary questions when applicable. The primary question is the main question of the review. The secondary questions are usually linked to possible subgroup analyses. This section may also present definitions of the primary question components (e.g. the subject population, intervention and outcome measure) but see also ‘study eligibility criteria’ below.


This section should describe the design and conduct of the review. Although the methods may be somewhat repetitive of the protocol they should be given in full. Direct citation of the protocol should be made here. A clear description of all review stages should typically follow the format below;

Deviations from the protocol

Here describe any differences in methods to the ones proposed in the protocol including changes to searching, eligibility criteria and screening process, critical appraisal, data coding and synthesis. Please justify these changes.

Search for articles

Here all searches should be described in sufficient detail so as to be replicable. The following bullet points are a guide to the subsections and detail required in describing the search strategy, the sources searched and how the search was conducted, including limitations.

  • Search terms and strings: How were decisions made and justified on the search terms and languages in which search was conducted? All search strings used for each of the searches conducted (including searches via search engines, publication databases and specialist websites) should be provided in a supplementary file. Search strings should be provided exactly as they were used, including combinations of terms using Boolean operators (AND, OR, NOT, etc.), wildcards (to include alternative forms of words, plurals, etc.) or any other special characters. Where searches could not be conducted using search strings, but individual search terms were used, those terms should also be listed. Trial development of search strings (if not included in the protocol) may also be included as an Additional File.
  • Search limitations: State date ranges imposed on the search with justification. State all languages in which searches were conducted and any limitations this may impose on the review.
  • Search sources: List all publication databases, citation indexes and other services that were searched, including details of institutional subscriptions used to access these services (or date ranges subscribed for each database searched), search options (e.g. ‘topic words’ or ‘full text’ search facility) and dates of searches.
  • Search sources: List all search engines used, including a description of search options (e.g. title search) and dates of searches. Justify any strategy to limit the number of search results considered. Describe how you coped with limitations to using search strings if any.
  • Search sources: Searches of organisational websites should be described, including a list of websites searches, dates of searches, any filtering or limitations applied.
  • Supplementary searches: Supplementary searches should also be described so as to be replicable. These include Bibliographical searches, ‘snowballing’ or obtaining literature from experts or stakeholders (via open calls and similar).
  • Estimating the comprehensiveness of the search: If not reported at the protocol stage, please state how you tested the comprehensiveness of your search. For example, did you compile a benchmark list of relevant studies to test the sensitivity of your searches?
  • Search results: You may also describe how you assembled a library of search results i.e. how you combined and deduplicated search results and which reference (or review) management software you used to do this.

Article screening and study eligibility criteria

Screening process

Describe the article screening process and decisions regarding eligibility, at title, abstract, full-text level. Describe how the consistency of eligibility decisions was measured and reported, and how disagreements between reviewers were resolved so as to inform subsequent decisions. Results of consistency checking at all stages must be provided.

Confirm the exclusion of the review team members (who have also authored articles considered within the review) from decisions regarding inclusion or study validity assessment of their own work.

Eligibility criteria

Eligibility criteria should be precisely defined (e.g. reliance on broad and potentially ambiguous terms should be avoided) and expressly related to each key element of the question. Here describe criteria and definitions followed to include eligible articles so that this stage is transparent and replicable. You may add examples of both eligible and ineligible articles to clarify the criteria. Organise this section according to following subsections (or equivalent for other question types):

  • Eligible population(s) or subject(s)
  • Eligible intervention(s) or exposure(s)
  • Eligible comparator(s) (if appropriate)
  • Eligible outcomes
  • Eligible types of study design
  • Any additional criteria

Study validity assessment

If study validity assessment was undertaken, describe how you attempted a preliminary assessment of the validity of included studies. This may be a report of the design of each study or an assessment of internal validity (risk of bias). Report any checklists used. Describe how the information from this assessment was used in synthesis and how repeatability of critical appraisal of study validity was tested.

Data coding strategy

State what categories of meta-data were intended to be coded. Describe here the methods by which meta-data from each study were extracted so that the process can be replicated. Specifically, state how meta-data from included studies were recorded. Provide any spreadsheets (codebooks and data coding forms) used. State how you tested the consistency of the data coding process among reviewers. Describe any process for obtaining and confirming missing or unclear information or data from authors of studies included in this process.

Data mapping method

Describe here how you collated studies in order to present them as a map. Describe the methods used to identify and/or prioritise key knowledge gaps (unrepresented or underrepresented subtopics that warrant further primary research) and knowledge clusters (well-represented subtopics that are amenable to full synthesis via systematic review).

Review findings

Findings of each stage of the map (e.g. search statistics, eligibility, critical appraisal) should be clearly reported. A narrative synthesis of included studies (usually in tabular form) may be presented (can be as additional material when appropriate). Subsections should follow the format:

Review descriptive statistics (sub-headings as applicable)

Report here the number of articles and the studies therein found in the search. A flow diagram reporting all stages of the inclusion/exclusion process, from search results to full text eligibility, should be presented.

Descriptive statistics should be provided on any relevant information on the distribution of the articles found (e.g. geographical, temporal, institutional) in order to assess potential gaps or bias in the evidence. For full transparency, additional files are expected here including:

Tables of search results showing where eligible articles were found (i.e. through which database etc) A full reference list of all eligible articles A list of studies excluded at full text together with reasons for exclusion (reasons for exclusion should match your eligibility criteria).

Mapping the quantity of studies relevant to the question

Present here a figure or a database, showing how the relevant literature is organised (categories, coding...) according to transparent, replicable criteria. This map should be readily updatable.

Mapping the quality of studies relevant to the question

The map should provide some preliminary estimate of the quality of the available evidence. This may involve providing a description of the design of each study (or of a representative sample of studies).

This section should include an explanation of how the map can be used to find appropriate studies and observations on the distribution of articles and relative quantity and quality of available evidence with respect to the broad question and how the question might be broken down to enable full systematic review(s) to be conducted in future. Describe knowledge gaps (unrepresented or underrepresented subtopics that warrant further primary research) and knowledge clusters (well-represented subtopics that are amenable to full synthesis via systematic review)

Limitations of the map

A detailed and reflective discussion of the limitations of the review is expected here, including limitations due to the search strategy (limitations of the review methods), as well as limitations due to underlying bias within the studies found such as baseline bias and confounding variables (limitations of the evidence base). Please do not provide a discussion section that includes speculation or expert opinion concerning the review findings.


This section should be divided into:

Implication for Policy/Management

This section summarises the state of the evidence base in terms of the distribution and abundance of studies captured in the map in relation to different elements of the question. Potential for unpacking the broad question and enabling more detailed evidence synthesis should be highlighted. The intention is to inform and any form of advocacy should be excluded.

Implication for Research

This section summarises the shortcomings of the current evidence base in terms of knowledge gaps and the need for primary research. In this section some advocacy for research is permissible provided it is clearly justified by the review outcome. This should take the form of recommendations for future study designs that would improve the evidence base. 


All manuscripts must contain the following sections under the heading 'Declarations':

  • Ethics approval and consent to participate
  • Consent for publication
  • Availability of data and materials
  • Competing interests
  • Funding
  • Authors' contributions
  • Acknowledgements
  • Authors' information (optional)

Please see below for details on the information to be included in these sections.

If any of the sections are not relevant to your manuscript, please include the heading and write 'Not applicable' for that section. 

Ethics approval and consent to participate

Manuscripts reporting studies involving human participants, human data or human tissue must:

  • include a statement on ethics approval and consent (even where the need for approval was waived)
  • include the name of the ethics committee that approved the study and the committee’s reference number if appropriate

Studies involving animals must include a statement on ethics approval and for experimental studies involving client-owned animals, authors must also include a statement on informed consent from the client or owner.

See our editorial policies for more information.

If your manuscript does not report on or involve the use of any animal or human data or tissue, please state “Not applicable” in this section.

Consent for publication

If your manuscript contains any individual person’s data in any form (including any individual details, images or videos), consent for publication must be obtained from that person, or in the case of children, their parent or legal guardian. All presentations of case reports must have consent for publication.

You can use your institutional consent form or our consent form if you prefer. You should not send the form to us on submission, but we may request to see a copy at any stage (including after publication).

See our editorial policies for more information on consent for publication.

If your manuscript does not contain data from any individual person, please state “Not applicable” in this section.

Availability of data and materials

All manuscripts must include an ‘Availability of data and materials’ statement. Data availability statements should include information on where data supporting the results reported in the article can be found including, where applicable, hyperlinks to publicly archived datasets analysed or generated during the study. By data we mean the minimal dataset that would be necessary to interpret, replicate and build upon the findings reported in the article. We recognise it is not always possible to share research data publicly, for instance when individual privacy could be compromised, and in such instances data availability should still be stated in the manuscript along with any conditions for access.

Authors are also encouraged to preserve search strings on searchRxiv, an archive to support researchers to report, store and share their searches consistently and to enable them to review and re-use existing searches. searchRxiv enables researchers to obtain a digital object identifier (DOI) for their search, allowing it to be cited. 

Data availability statements can take one of the following forms (or a combination of more than one if required for multiple datasets):

  • The datasets generated and/or analysed during the current study are available in the [NAME] repository, [PERSISTENT WEB LINK TO DATASETS]
  • The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
  • All data generated or analysed during this study are included in this published article [and its supplementary information files].
  • The datasets generated and/or analysed during the current study are not publicly available due [REASON WHY DATA ARE NOT PUBLIC] but are available from the corresponding author on reasonable request.
  • Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.
  • The data that support the findings of this study are available from [third party name] but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of [third party name].
  • Not applicable. If your manuscript does not contain any data, please state 'Not applicable' in this section.

More examples of template data availability statements, which include examples of openly available and restricted access datasets, are available here.

BioMed Central strongly encourages the citation of any publicly available data on which the conclusions of the paper rely in the manuscript. Data citations should include a persistent identifier (such as a DOI) and should ideally be included in the reference list. Citations of datasets, when they appear in the reference list, should include the minimum information recommended by DataCite and follow journal style. Dataset identifiers including DOIs should be expressed as full URLs. For example:

Hao Z, AghaKouchak A, Nakhjiri N, Farahmand A. Global integrated drought monitoring and prediction system (GIDMaPS) data sets. figshare. 2014.

With the corresponding text in the Availability of data and materials statement:

The datasets generated during and/or analysed during the current study are available in the [NAME] repository, [PERSISTENT WEB LINK TO DATASETS].[Reference number] 

If you wish to co-submit a data note describing your data to be published in BMC Research Notes, you can do so by visiting our submission portal. Data notes support open data and help authors to comply with funder policies on data sharing. Co-published data notes will be linked to the research article the data support (example).

Competing interests

All financial and non-financial competing interests must be declared in this section.

See our editorial policies for a full explanation of competing interests. If you are unsure whether you or any of your co-authors have a competing interest please contact the editorial office.

Please use the authors initials to refer to each authors' competing interests in this section.

If you do not have any competing interests, please state "The authors declare that they have no competing interests" in this section.


All sources of funding for the research reported should be declared. If the funder has a specific role in the conceptualization, design, data collection, analysis, decision to publish, or preparation of the manuscript, this should be declared.

Authors' contributions

The individual contributions of authors to the manuscript should be specified in this section. Guidance and criteria for authorship can be found in our editorial policies.

Please use initials to refer to each author's contribution in this section, for example: "FC analyzed and interpreted the patient data regarding the hematological disease and the transplant. RH performed the histological examination of the kidney, and was a major contributor in writing the manuscript. All authors read and approved the final manuscript."


Please acknowledge anyone who contributed towards the article who does not meet the criteria for authorship including anyone who provided professional writing services or materials.

Authors should obtain permission to acknowledge from all those mentioned in the Acknowledgements section.

See our editorial policies for a full explanation of acknowledgements and authorship criteria.

If you do not have anyone to acknowledge, please write "Not applicable" in this section.

Group authorship (for manuscripts involving a collaboration group): if you would like the names of the individual members of a collaboration Group to be searchable through their individual PubMed records, please ensure that the title of the collaboration Group is included on the title page and in the submission system and also include collaborating author names as the last paragraph of the “Acknowledgements” section. Please add authors in the format First Name, Middle initial(s) (optional), Last Name. You can add institution or country information for each author if you wish, but this should be consistent across all authors.

Please note that individual names may not be present in the PubMed record at the time a published article is initially included in PubMed as it takes PubMed additional time to code this information.

Authors' information

This section is optional.

You may choose to use this section to include any relevant information about the author(s) that may aid the reader's interpretation of the article, and understand the standpoint of the author(s). This may include details about the authors' qualifications, current positions they hold at institutions or societies, or any other relevant background information. Please refer to authors using their initials. Note this section should not be used to describe any competing interests.


Footnotes can be used to give additional information, which may include the citation of a reference included in the reference list. They should not consist solely of a reference citation, and they should never include the bibliographic details of a reference. They should also not contain any figures or tables.

Footnotes to the text are numbered consecutively; those to tables should be indicated by superscript lower-case letters (or asterisks for significance values and other statistical data). Footnotes to the title or the authors of the article are not given reference symbols.

Always use footnotes instead of endnotes.

Additional Files

Additional files should include a title and description of data. Please note the ROSES form should be listed as an additional file. 


Examples of the Vancouver reference style are shown below.

See our editorial policies for author guidance on good citation practice

Web links and URLs: All web links and URLs, including links to the authors' own websites, should be given a reference number and included in the reference list rather than within the text of the manuscript. They should be provided in full, including both the title of the site and the URL, as well as the date the site was accessed, in the following format: The Mouse Tumor Biology Database. Accessed 20 May 2013. If an author or group of authors can clearly be associated with a web link, such as for weblogs, then they should be included in the reference.

Example reference style:

Article within a journal

Smith JJ. The world of science. Am J Sci. 1999;36:234-5.

Article within a journal (no page numbers)

Rohrmann S, Overvad K, Bueno-de-Mesquita HB, Jakobsen MU, Egeberg R, Tjønneland A, et al. Meat consumption and mortality - results from the European Prospective Investigation into Cancer and Nutrition. BMC Medicine. 2013;11:63.

Article within a journal by DOI

Slifka MK, Whitton JL. Clinical implications of dysregulated cytokine production. Dig J Mol Med. 2000; doi:10.1007/s801090000086.

Article within a journal supplement

Frumin AM, Nussbaum J, Esposito M. Functional asplenia: demonstration of splenic activity by bone marrow scan. Blood 1979;59 Suppl 1:26-32.

Book chapter, or an article within a book

Wyllie AH, Kerr JFR, Currie AR. Cell death: the significance of apoptosis. In: Bourne GH, Danielli JF, Jeon KW, editors. International review of cytology. London: Academic; 1980. p. 251-306.

OnlineFirst chapter in a series (without a volume designation but with a DOI)

Saito Y, Hyuga H. Rate equation approaches to amplification of enantiomeric excess and chiral symmetry breaking. Top Curr Chem. 2007. doi:10.1007/128_2006_108.

Complete book, authored

Blenkinsopp A, Paxton P. Symptoms in the pharmacy: a guide to the management of common illness. 3rd ed. Oxford: Blackwell Science; 1998.

Online document

Doe J. Title of subordinate document. In: The dictionary of substances and their effects. Royal Society of Chemistry. 1999. of subordinate document. Accessed 15 Jan 1999.

Online database

Healthwise Knowledgebase. US Pharmacopeia, Rockville. 1998. Accessed 21 Sept 1998.

Supplementary material/private homepage

Doe J. Title of supplementary material. 2000. Accessed 22 Feb 2000.

University site

Doe, J: Title of preprint. (1999). Accessed 25 Dec 1999.

FTP site

Doe, J: Trivial HTTP, RFC2169. (1999). Accessed 12 Nov 1999.

Organization site

ISSN International Centre: The ISSN register. (2006). Accessed 20 Feb 2007.

Dataset with persistent identifier

Zheng L-Y, Guo X-S, He B, Sun L-J, Peng Y, Dong S-S, et al. Genome data from sweet and grain sorghum (Sorghum bicolor). GigaScience Database. 2011.

Figures, tables and additional files

See General formatting guidelines for information on how to format figures, tables and additional files.

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Annual Journal Metrics

  • 2022 Citation Impact
    3.3 - 2-year Impact Factor
    5.1 - 5-year Impact Factor
    1.084 - SNIP (Source Normalized Impact per Paper)
    0.967 - SJR (SCImago Journal Rank)

    2023 Speed
    11 days submission to first editorial decision for all manuscripts (Median)
    148 days submission to accept (Median)

    2023 Usage
    582 Altmetric mentions