Authorship and co-authorship in medical and health research

Authorship is one of the most controversial topics in medical research ethics. Accusations of unjustified authorship are the most frequent cause of investigations into dishonesty in medical research. In addition, disagreement about questions of authorship have created dissension in many research groups and destroyed many friendships. There are several key questions: Why is it so important to be cited as an author? Who (and what) qualifies for authorship? When an article has a number of authors, in what sequence should their names appear? Who actually decides the list of authors of a scientific article?

The development

NB! This article is under revision. Some references are outdated (February 2021). 

Basically an author is a person who has written something, and who thus has responsibility for the content as well as the intellectual rights to the content. In scientific publications, authorship has developed into a far more complicated concept, partly because individual publications are acquiring an increasing number of authors.

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Medical publishing has developed from being primarily a source of information to clinicians to becoming an activity for researchers to acquire credit points. Medical journals are no longer just channels for knowledge dissemination, but also meeting places for researchers and arenas for assessment of productivity and competence. This has led to a situation in which an author of a scientific article is not necessarily the person who has written the words that are in print, but he/she has perhaps contributed to other aspects of the research project.

The importance of multiple authorship has grown rapidly, as has the number of authors per scientific article. Medical articles recorded in Medline in 1950 had an average of 1.5 authors. In 1985 this number had increased to three, and in 2011 there was an average of five authors per registered article.

The increase in multi-authorship is partly attributable to the fact that medical research has become more multi-disciplinary and international, and is often conducted as collaborative projects with many participants. However, it can also be attributed to the increased attractiveness of being included on a list of authors for reasons of merit.

Moreover, authors of scientific articles and their institutions are now financially rewarded, often with higher sums according to the prestigiousness of the journals in which their articles are published. As a result, not only the authors' names but also their institutional affiliation and address have received greater attention.

The problems

Scientific authorship generally involves two relationships, an "external" one between the author(s) and reader/public, and an "internal" one between authors, institutions, adjudication committees etc.

Responsibility is the keyword with regard to the external relationship. Authors are guarantors of the content of their texts. Moreover, responsibility to readers and the public requires that the author or authors can stand by the message that is presented. In several cases of scientific dishonesty, the authors have retrospectively attempted to abrogate this responsibility by claiming that they had no knowledge of what had happened, and that their role in the preparation of the article was actually insignificant.
Fairness is the keyword with regard to the internal relationship. If authorship is to be used as a basis for merit, the same criteria must be used in all research communities. Varying requirements for co-authorship create an erroneous and unfair basis for comparisons, for example between applicants for the same position who come from environments with different traditions of authorship.

A review of 118 studies of authorship in different academic disciplines revealed four problem areas: the perception and definition of authorship, the sequence of authors, ethical and unethical authorship practice, and questions regarding the relationship between supervisors and students or technical personnel (Marušić et al 2011).

Even when there is agreement on who the authors of an article are, disagreement may arise regarding the sequence of authors. Traditionally the lead author is the person who has put most work into the project, and often the last author is a more experienced supervisor, but otherwise the sequence is poorly defined.

Three problems related to authorship are particularly relevant to medical and health research:

  1. "Gift authorship" is a situation in which persons with a relatively tenuous association with the project are included on the list of authors, perhaps in the hope that they will reciprocate the favour next time around.
  2. "Guest authorship" is the term used when particularly well-known or prominent persons are unfairly invited to be included on the list of authors because it is assumed that this will strengthen the project and increase the chance of publication.
  3. "Ghost authorship" is the term used when persons who definitely should be included among the authors are omitted – willingly or unwillingly.

A very particular problem is created by the decision-making process associated with authorship, as it is often the head of a department or research project who makes the decision. It is not easy for a young PhD candidate to object to the decisions of an older professor.
Unfair authorship is a frequent occurrence. A review of 14 different questionnaire surveys showed that an average of 29% of the researchers reported experiences of unfair authorship (Marušić et al 2011). A survey of articles published in 2008 in six prestigious general medical journals revealed that one of four original articles had at least one unjustified author. In one of ten original articles an author's name that should have been included was absent (Wislar et al 2011). This underlines the need for measures (Baskin & Gross 2011).

Attempted solutions

For the first time in 1985, the International Committee of Medical Journal Editors (the Vancouver Group) standardised criteria for authorship. The core notion was that authorship is an intellectual activity and that ideas, analyses and not least the writing itself are the essence of scientific authorship. (See The Vancouver Guidelines.)

The Vancouver criteria have since undergone several revisions. Although these criteria have gradually become an international standard, with the support of the medical faculties in Norway, among others, this has not solved the problems. This is partly because the criteria have not been made sufficiently known in the research communities, but primarily because the rules are not followed even by those who are familiar with them. A survey of Norwegian medical researchers has shown that it is easier to agree with the criteria than to comply with them (Nylenna et al 2014).

The discrepancy between formal rules and practice has resulted in proposals to abandon the entire concept of authorship as it is today. A new system was suggested, based on contributors and a specified list of the input that different people have contributed to a project. This system of contributors has never been successful, partly because only a few journals have introduced it, and partly because no international taxonomy (standardised classification) of different forms of contribution exists. However, most important of all is probably the fact that being listed at the end of an article immediately before the reference list is not perceived as appealing and as providing credit points. It is still the authors who are named below the title of the article, and who are indexed in literature databases.

For a long time, one of the main objections to the authorship criteria was that researchers who have performed most of the practical work on a study do not fulfil the requirements. In order to meet this objection, the Vancouver Group revised the criteria in 2000.

Several cases of research fraud have revealed a need for the authors of an article to take joint and total responsibility for the integrity of all aspects of the work. For this reason a fourth criterion for authorship (d) was included in 2013.

A small number of journals have prepared their own explicit criteria for authorship, but most medical journals, faculties and research institutions have endorsed those of the Vancouver Group.

The Vancouver Group's criteria for authorship

The Vancouver Group's criteria for academic authorship are now as follows (NB! This version of the recommendations is outdated, please refer to for an up to date version):
In addition to being accountable for the parts of the work he or she has done, an author should be able to identify which co-authors are responsible for specific other parts of the work. In addition, authors should have confidence in the integrity of the contributions of their co-authors.

Authorship shall be based exclusively on the following four criteria:

a) Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work;

b) Drafting the work or revising it critically for important intellectual content;

c) Final approval of the version to be published;

d) Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

More details on the Vancouver Group's criteria for authorship may be found on:
In addition to knowledge of and compliance with the existing rules and guidelines, there are two precautions that may be beneficial to any research project:

  1. Decide on the list of authors (and the sequence) as early as possible;
  2. Agree on a way of dealing with possible disagreements with regard to authorship.

This article has been translated from Norwegian by Jane Thompson, Akasie språktjenester AS.