Authorship · Reference
What is the order of authorship?
The order of authorship is the sequence in which authors are listed in a publication’s byline; the convention varies by discipline, but it commonly signals relative contribution, with the most important positions at the start and end of the list.
The step most authors miss
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What the positions usually mean
In most experimental sciences, author order is informative. The first author is conventionally the person who did the most hands-on work and led the writing — often a doctoral student or postdoc. The last author is typically the senior researcher or principal investigator who conceived or supervised the project and provided the laboratory and funding. Middle positions are read, loosely, as decreasing contribution from the front, although this signal is weak and inconsistent.
These conventions are not universal rules — they are norms, and they are precisely the information that a structured contribution statement is designed to make explicit rather than leave to inference from position.
Disciplinary differences
Conventions vary sharply by field. In much of mathematics, economics and parts of the humanities, authors are listed alphabetically by surname, so order carries no contribution signal at all. In high-energy physics and some large collaborations, hundreds or thousands of authors may be listed alphabetically or by collaboration rules. In the life and biomedical sciences the first-author / last-author convention is strong. Because of this variation, the same byline position can mean very different things in different disciplines, and readers should not assume a single rule applies everywhere.
Equal contribution and shared positions
Where two or more authors contributed equally, journals allow joint first authorship (or joint last authorship), marked with a symbol and an "these authors contributed equally" footnote. This addresses the limitation that a strict linear order cannot represent two genuinely equal contributions. Evaluation committees vary in how they credit shared first authorship, which is one reason transparent contribution statements are valuable.
Order disputes and CRediT
Author order is one of the most common sources of authorship disputes, because position carries career weight but the rules are informal and discipline-specific. CRediT does not encode or resolve author order — it deliberately leaves ordering to disciplinary convention — but it reduces the stakes of the argument by recording each person’s actual roles, so credit no longer rests solely on a position in a list. The most reliable way to prevent order disputes is to agree the order, and the basis for it, at the start of a project and to record any changes as contributions evolve.
Key facts
At a glance
- First author: usually the largest hands-on contribution; led the writing
- Last author: usually the senior PI / supervisor
- Middle: loosely decreasing contribution; a weak signal
- Alphabetical: the norm in maths, economics and parts of the humanities
- Equal: joint first authors marked with an "equal contribution" footnote
- CRediT: does not encode author order; records roles instead
Common questions
FAQ
What does the order of authors mean?+
In many experimental sciences the first author contributed most and led the writing, while the last author is the senior supervisor. Middle positions loosely indicate decreasing contribution, but the signal is weak and varies by discipline.
Is author order always by contribution?+
No. In mathematics, economics and parts of the humanities, authors are commonly listed alphabetically by surname, so order carries no contribution signal at all.
Who is more important, the first or last author?+
Neither is universally "more important". The first author typically did the most hands-on work; the last author typically supervised and secured funding. Their relative weight depends on the field and the specific project.
What is joint first authorship?+
Joint (or co-) first authorship is when two or more authors contributed equally and share the first position, marked with a symbol and a footnote stating that they contributed equally.
How can author-order disputes be avoided?+
Agree the order, and the basis for it, at the start of the project, record it, and revisit it if contributions change. A CRediT contributor-roles statement also reduces the stakes by recording what each person actually did.
