Co-authorship

About the author: Bjørn Hofmann is professor at Centre for Medical Ethics, University of Oslo, and at Department of Health Sciences, NTNU Gjøvik

An author is defined as someone who has written a text. So why is authorship one of the most contentious issues in research – and one of the most important topics in science ethics and research integrity? The answer lies largely in disagreements over several key issues: 

1. Contributions (content): What contributions are required to be recognised as a (co-)author? Scientific contributions extend beyond just writing. Is conceiving the idea or collecting data enough?  
2. Extension: How much must someone contribute? What contributions are required to qualify as a co-author?  
3. Procedure: How do we determine the order of authorship?  
4. Authority: Who decides on co-authorship and the order of authors?  
5. Accountability: What responsibility does a co-author bear for errors or shortcomings in a publication?  

The reason why scientific authorship is important in research, and why these questions play a central role, is that authorship fulfils a number of important functions: 

• Crediting: Authorship reflects a scientific (intellectual) contribution and functions as a credential.  
• Recognition: Authorship recognises and provides the listed individuals with professional acknowledgement.  
• Accountability: Authorship assigns responsibility to those named as authors. 
• Evaluation: Authorship is used to evaluate researchers, including in applications for posts and funding decisions. 
• Collaboration: Co-authorship indicates collaboration and participation in research networks, which play a key role in evaluation and recognition of research and research groups.

Its importance in recognition and evaluation accords co-authorship significant value in the research community, making the questions above (1-5) particularly relevant.  
As with other forms of societal values, disputes often arise. Moreover, some individuals try to obtain such values unethically. This has led to a wide range of questionable and unethical authorship practices. 

Unethical authorship practices  

Gift authorship: As the name suggests, authorship is given as a “gift,” often with the aim of some form of reciprocity. 

Honorary authorship: authorship granted (without a qualifying contribution), as a gesture of respect or to honour someone. Honorary authorship is often viewed as a form of gift authorship.  

Guest authorship: Involves adding (often prominent) individuals to the author list to lend credibility or prestige to the “host” or publication. Related to honorary authorship.  

Ghost authorship: A person writes the entire text or makes substantial contributions but is not credited as a (co-)author.  

Excluded authorship: An individual who has made a substantial contribution is excluded from the list of (co-)authors. Also commonly referred to as “orphan authorship”.  

Mandatory (forced) authorship: An individual, such as a research leader, claims the right to be listed as a co-author in all publications issued by their project or institution. Members of the research team feel obliged to include the person in question as a co-author.  

Falsified (forged) authorship: An individual is listed as a co-author without their knowledge or the wrong person is included in the list of authors. Also known as “forged authorship”.  

Duplicate publications: Publishing the same or similar content with modified author lists to artificially inflate recognition.  

Fictitious (fake) authorship: Fictitious individuals are listed as co-authors. For example a cat was listed as a co-author in a much publicised physics article and fictitious authors can appear in predatory journals.  

While all these forms of authorship lead to improper crediting and recognition of individuals, they can also confer accountability, for instance, when a publication is found to contain errors or has been produced dishonestly. There are numerous cases where beneficiaries of gift authorship have been implicated in research misconduct.  

Different traditions – different authorship norms 

Authorship norms differ across academic fields: In medicine, health sciences and life sciences, research often involves multiple co-authors. This has given rise to many authorship conflicts and highlighted the need for an explicit system of norms at an early stage. The International Committee of Medical Journal Editors (ICMJE) addressed this by creating the Vancouver Recommendations, which specify the contributions required and the responsibilities involved in being a co-author. See below. Studies in Norway and Scandinavia reveal that a high proportion of early-career researchers experience authorship disputes.  

In mathematics, natural sciences and technology, authorship is generally reserved for those who have made substantial intellectual contributions to the research, such as formulating the problem, designing the study, analysing data or drafting the manuscript. The Guidelines for Research Ethics in Science and Technology also refer to the Vancouver Recommendations.

In social sciences and humanities, substantial contributions to the project are required to be recognised as a co-author. According to the Guidelines for Research Ethics in the Social Sciences and the Humanities tasks such as data collection, supervision or funding alone do not qualify someone for co-authorship.  
Similarly, the norms for the order of authorship vary somewhat across different scientific disciplines. See below.  

Contributions: What contributions are required to qualify as a co-author?  

Deciding what qualifies as a contribution worthy of co-authorship is a critical issue in research. If the criteria are too strict, individuals who provide limited but important contributions (such as statisticians in empirical studies) might be excluded from co-authorship. On the other hand, if the criteria are too lenient, authorship risks losing its value as a measure of credit, merit and valuation (see above). The widely applied Vancouver Recommendations (updated in January 2024), require a co-author to: 

1. make substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND  
2. draft the work or review it critically for important intellectual content; AND 
3. give final approval of the version to be published; AND 
4. agree 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. 

There has been much debate about how to interpret the recommendations, resulting in multiple revisions over the years. While the first criterion has optional elements, the last three are mandatory requirements for inclusion as a co-author. The following contributions are explicitly excluded as qualifying for authorship: research funding, general supervision of a research group, general administrative support, assistance with writing, technical editing, language editing and proofreading.  

Scope: How much must someone contribute?

The Vancouver Recommendations and similar publication ethics guidelines go into a little more detail about how much someone should contribute to qualify as a co-author: The contributions must be substantial. Minor involvement in design or data collection is therefore not sufficient. Additionally, co-authors must have either drafted a version of the manuscript or provided substantial intellectual contributions during revisions of the study. General feedback or language suggestions alone therefore do not meet the criteria. Researchers must have made substantial intellectual contributions. 

Procedure: How do we determine the order of authorship? 

Different scientific disciplines have different ways of determining the order of authorship – and these conventions evolve over time. In medicine, health sciences and life sciences, the first author is typically the individual who made the greatest contribution to the study, while the last author is often a senior researcher (such as a supervisor, who takes overall responsibility for the study). The roles of middle authors depend on the norms of the specific field.  

In mathematics, authors are often listed alphabetically, although the approach can vary also here. In natural sciences and technology, these can often be multiple co-authors. Some publications can have thousands of co-authors. 

In social sciences, the first author is usually the one who has contributed most to the project. In some areas of the humanities, authors are traditionally listed alphabetically, but again practices can vary. Historically, these disciplines have had fewer authors per publication, but this trend has shifted over time.  

In interdisciplinary research, authorship norms and ordering practices vary. However, the Vancouver Recommendations are increasingly being adopted as a standard in these contexts too. 

Authority: Who decides co-authorship and the order of authorship? 

Ideally, the person who contributes the most to the research should determine the list of authors (unless it is arranged alphabetically). Anyone (who meets the first criterion of the Vancouver Recommendations) may qualify as a co-author and should be given the chance to contribute enough to earn co-authorship. Those who do not qualify as co-authors, but who still have contributed, should be named and thanked in the acknowledgements section.  

Unfortunately, the person who makes the greatest contributions does not always determine the author list in practice. Research leaders, project leaders and supervisors often take control of this process, sometimes inviting individuals who do not meet the qualifications to be listed as co-authors. This practice is problematic due to asymmetric power dynamics, and also undermines the credibility of the authorship institution.  

Accountability: What responsibility does a co-author bear for errors in a publication? 

As we have seen above, the Vancouver Recommendations stipulate that all co-authors are accountable when they become co-authors and must assume responsibility for any errors that may be present in the publication. However, in complex research projects with multiple specialised contributions, it can obviously be difficult for co-authors to fully understand or be accountable for each individual aspect of the research. To address this, co-authors are typically held accountable for the parts of the research they directly contributed to. Additionally, they must be able to identify which co-authors are responsible for other parts of the work and trust the integrity of those contributions. In other words, simply claiming, “I was only responsible for my part,” does not hold.  

Artificial authorship 

Artificial intelligence (AI), machine learning (ML) and large language models (LLMs) have introduced ground-breaking methods for generating meaningful text, challenging traditional concepts of authorship. These models rely on massive datasets, often containing text created by others. This gives rise to the following issues with regard to the traditional roles of authorship (see also above):  
Crediting: Authorship may become an unreliable way to credit intellectual contributions (such as originality).  

• Recognition: Being listed as an author may no longer provide a basis for professional acknowledgement.  
• Accountability: As a listed author, persons may be held accountable for content they did not write or fully understand.  
• Evaluation: Authorship may lose its significance as a metric for evaluating researchers’ work.  
• Collaboration: Authorship may lose its role as an indicator of networks or collaboration.  

In summary, AI and ML could diminish the value of authorship, potentially driving a need for new ways to credit, recognise and evaluate research contributions. The use of AI/ML-generated text naturally also poses other ethical challenges in research, including concerns about plagiarism and intellectual property rights.  

Ethical norms for (co-)authorship  

The ethical norms for (co-)authorship are primarily internal to the research community, i.e. the professional ethics of scientists and as such rooted in science ethics. These are mainly social (and not epistemic) norms. 

• Honesty: Researchers must be honest about their own and others’ contributions.  
• Transparency: Researchers must be transparent about the origin and progression of the scientific research. This means that anyone eligible to be a co-author should have the chance to contribute sufficiently to meet the criteria. They must also disclose any potential conflicts of interest that might influence authorship decisions. 
• Credibility: Researchers must be veracious (report truthfully) about the contributions of all individuals involved in the research.  
• Accountability: Researchers must take responsibility for the parts of the work they contributed to and be prepared to give an account of the contributions of others and the overall integrity of the research.  
• Collegiality: Researchers must treat colleagues with respect and uphold their integrity. It is also important to contribute to a collegiate culture that supports these ethical norms.  
• Acknowledgement: Researchers must acknowledge the contributions of others to a scientific study.  
• Integrity: Researchers must demonstrate the ability to act in accordance with the norms for (co-)authorship and publication ethics. This includes avoiding practices such as guest authorship, gift authorship, honorary authorship, ghost authorship or any other inappropriate (co-)authorship practices, as outlined above.  

Beyond these internal norms, it is crucial to acknowledge the imbalance of power and status, which can make it difficult for junior researchers to raise concerns about authorship. Experienced researchers must take responsibility that extends beyond just their own contributions to the work.  

Co-authorship in interdisciplinary and international collaborations  

Navigating co-authorship in interdisciplinary and international collaborations can be challenging for several reasons. Collaboration partners from different countries and academic traditions may have differing norms for or interpretations of co-authorship practices. Communication differences can also create problems, while contrasting leadership styles in research can further complicate the process. Additionally, differing conventions for recognition and evaluation may create conflicting expectations for publication. Countries may also have divergent rules for intellectual property rights, research integrity and collegiality that could be reflected in co-authorship norms.  

These (and other) authorship issues can be prevented in interdisciplinary and international research collaborations by drawing up explicit agreements at an early stage, holding regular meetings (where agreements are updated), embedding clear and explicit research leadership, transparently and inclusively addressing authorship as a topic, and providing training in each other’s authorship norms and ethical standards.  

Some practical advice 

While guidance from the Vancouver Recommendations and similar frameworks addresses the issues mentioned in the introduction, and bearing in mind that AI/ML may in future reduce the value of authorship and its associated controversies, authorship disputes will remain a common source of conflict. So here are some practical steps to help avoid these issues:  

The most important things are to thoroughly plan the study and to hold open and inclusive discussions about (co-) authorship expectations at the start of the project. Drafting a written agreement is also a good idea. There are many authorship agreement templates that can be used. It is important to update the agreement for any changes during the project, as changes are expected. 

A section outlining each contributor’s role can also be included in manuscripts or protocols (preferably at the beginning). Below are a few ways to do this:  

Potential co-author	Intended contribution	Summary actual contribution
Bjørn Hofmann	Design of study, contirbute to the analysis of data, draft manuscript, revision, approval	Design of the study, interpretation of results, draft manuscript, revision 1, revision 2, revision 3, approval
XXX	Contribute to design, data collection, analysis of data, audit, approval	Contribute to design, data collection, analysis of data, interpretation of results, revision 1, 2, 3, approval
Initials	Contribution	Date (or revision number)
BH and XXX	Design of the study	22.10.2024
XXX	Data collection	1.-30.11.2024
XXX	Analysis of data	15.-22.11.2024
BH	Interpretation of data	25.11.2024
BH	Draft manuscript	2.12.2024

 

Potential co-author	What is done to the manuscript?	When is it done?
XX and YY	Design of the study	22.10.2024
ZZ	Data collection	1.-30.11.2024
ZZ	Analysis of data	15.-22.11.2024
XX, YY, ZZ	Interpretation of data	25.11.2024
XX	Drafting manuscript	2.12.2024
XX	Revision of the manuscript	12.12.2024

Summary 

This article has attempted to address some key ethical challenges concerning (co-)authorship by identifying some common unethical authorship practices, referring to the various roles and functions of authorship, outlining ethical norms and principles for handling authorship disputes and offering some practical advice.  
As long as authorship has a value and plays so many important roles in research, conflicts and controversies will continue to arise. However, these issues can be mitigated and effectively managed by applying established authorship norms rooted in publication ethics.  

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This article has been translated from Norwegian by Samtext International AS. Proofreading by the author.