When submitting the manuscript, authors must provide a Code and Data Availability Statement describing compliance with the Journal's policy, outlined below.The editors will assess the declarations made in the statement prior to publication. The Journal's editors encourage authors to contact them if they believe they will encounter difficulties in complying with the policy. If the article is accepted for publication, the Code and Data availability statement will be published as a supplement to the final article. We outline the policy and required information below, as well as providing some guidance and examples on how to comply with this policy.

Basic Policy

The Journal stronlgy suggests that authors make all code and, if possible, data underlying the findings described in their manuscript available without restriction. If data cannot be made available due to confidentiality concerns, then this should be stated, together with a description of how others could potentially access the data.

Code and, where appropriate, data shall be deposited in repositories that meet accepted criteria as trustworthy digital repositories. The Journal does NOT publish supplementary materials itself. Personal websites, links to subscription-based online storage facilities (Dropbox, Google Drive, etc.), and online code repositories (Github, Bitbucket, etc.) are generally not acceptable, as they do not ensure persistence.

The Journal strongly encourages authors to also cite acceptable code and data repositories as part of the references. In general, acceptable code and data repositories provide persistent identifiers, such as DOIs, and maintain robust long-term archives.

This data policy will be implemented on January 1, 2020. Any paper submitted before that date will not have a data availability statement.

Required Information

  • The Code and Data Availability Statement must specify where code and data are each permanently deposited, listing the name(s) of repositories along with digital object identifiers or accession numbers for the relevant data sets.

  • The Code and Data Availability Statement must specify the conditions under which the deposited materials can be retrieved. A taxonomy is being developed, but a non-limiting list of possible options might be

    • access by download, possibly with (free) account creation and/or click-through license
    • access via a formal application process, specifying the conditions that an applicant may need to meet (nationality, membership in professional associations, security clearance, etc.).
    • for-fee access (purchase or subscription), stating the fee and conditions of use
  • The Code and Data Availability Statement must specify the archival and curation policy of the institution curating the objects. For instance, the materials might remain accessible for 5 years, or "permanently".


  • Repositories may be either subject-specific (where these exist) and accept specific types of structured data, or generalist repositories that accept multiple data types. We refer readers to the following sites and journals for guidance on appropriate repositories:

  • We note that typical "code repositories" (Github, Gitlab) and cloud-based storage systems (OneDrive, Google Drive, Dropbox, Amazon S3) do not qualify as permanent repositories, as objects in them can be deleted or reorganized at any time, and may rely on subscription services to remain available.
  • However, we also note that it is possible to link such repositories to formal archives. An example is Making Your Code Citable. Alternatively, some repositories include within their workflow the ability to generate permanent archives with DOIs (Open Science Framework, Figshare).