Content types

On this page: Article | Brief Communication | Comment | Editorial | Matters Arising | Perspective | Protocol | Review | Technology Feature


An Article is a substantial research study, with a complex story often involving several techniques or approaches. The main text (excluding abstract, Methods, references and figure legends) is typically no more than 4,000-4,500 words. The abstract is typically 150 words, unreferenced. Articles have up to 10 display items (figures and/or tables). An Introduction section is followed by sections headed Results, Discussion, Methods and Data Availability. The Results and Methods should be divided by topical subheadings; the Discussion may contain subheadings at the editors' discretion. As a guideline, Articles have around 60 references.

Articles include received and accepted dates. They may be accompanied by supplementary information. Articles are peer reviewed.

Brief Communication

A Brief Communication reports a concise study of high quality and broad interest. Brief Communications begin with a brief unreferenced abstract (3 sentences, usually no more than 70 words). The main text is typically 1,000-1,500 words, including abstract, references and figure legends, and contains no headings. Brief Communications normally have no more than 2 display items, although this may be flexible at the discretion of the editor. Brief Communications include a Methods and Data Availability section. As a guideline, Brief Communications have around 20 references.

Brief Communications include received and accepted dates. They may be accompanied by supplementary information. Brief Communications are peer reviewed.


Comment is a very flexible format; Comments may be on policy, science and society or purely scientific issues. The main criteria are that they should be of immediate interest to a broad readership and should be written in an accessible, non-technical style. Their length is typically 1,000-2,000 words. Because the content is variable, the format is also flexible. Comments do not normally contain primary research data, although they may present 'sociological' data (funding trends, demographics, bibliographic data, etc.). References typically do not exceed 25.

Comments include received and accepted dates. Comments are typically peer reviewed.


Editorials are written by the senior editorial team of the journal, under the direction of the Editor-in-Chief. They are not typically peer reviewed, although they can be at the discretion of the editorial team, and are published with received and accepted dates.

Matters Arising

Important scientific comments and clarifications on peer-reviewed articles published in npj Systems Biology and Applications may be submitted as Matters Arising. The guidelines for Matters Arising are outlined here.


Perspective is a format for scholarly reviews and discussions of the primary research literature that are too technical for a Commentary but do not meet the criteria for a Review—either because the scope is too narrow, or because the author is advocating a controversial position or a speculative hypothesis or discussing work primarily from one group. Two reviews advocating opposite sides in a research controversy are normally published as Perspectives. The text should not normally exceed 3,000 words. As a guideline, Perspectives allow up to 70 references.

Perspectives are always peer reviewed and include received and accepted dates.


Protocol is a format for step-by-step descriptions of procedures that users can take to the lab or clinic and immediately apply in their own research. All of our protocols have been proven to work already and a supporting primary research paper is a publication requirement. Each protocol contains a full list of reagents and equipment, timing information and step-by-step instructions for performing the experiment (with critical steps and cautions highlighted), as well as information on designing and adapting the technique, its advantages and limitations compared to alternatives, troubleshooting, analysing data and interpreting results. We also encourage authors to submit videos for steps that are technically challenging.

Protocols are always peer reviewed and include received and accepted dates.


A Review is an authoritative, balanced and scholarly survey of recent developments in a research field. The requirement for balance need not prevent authors from proposing a specific viewpoint, but if there are controversies in the field, the authors must treat them in an even-handed way. Reviews are normally 3,000-4,000 words, and illustrations are strongly encouraged. References are typically limited to 100, with exceptions possible. Citations should be selective. The scope of a Review should be broad enough that it is not dominated by the work of a single laboratory, and particularly not by the authors' own work.

Reviews include received and accepted dates. Reviews are always peer reviewed.

Technology Feature

A Technology Feature presents primary research data on a new technique that is likely to be influential. This format can also be review of technology or a resource, but should usually be its primary report in the literature. It may involve a new discovery to prove the usefulness of the technique or resource, but this is not a requirement. Technology Features have a format broadly similar to that of Articles, although many Technology Features are shorter than a typical Article. They begin with an unreferenced abstract (typically 150 words) followed by separate sections for Introduction, Results, Discussion, Methods and Data Availability. Up to 8 display items are allowed. As a guideline, Technology Features have around 60 references.

Technology Features include received and accepted dates. They may be accompanied by supplementary information. Technology Features are peer reviewed.