Last Author

What the last-author position signals

“Last author” refers to the name that appears at the end of a scholarly work’s byline. In fields that use a contribution-ranked author list — most consistently biomedicine, the life sciences, and much of the natural sciences — readers, hiring and promotion committees, and funders conventionally read that position as a signal that this person is the senior investigator: typically the principal investigator or lab head who conceived and supervised the study, secured the funding, and provided overall intellectual direction, while the first author did the hands-on experimental or analytical work.

It is important to be precise about what the position is and is not. Occupying the last-author slot is not itself one of the ICMJE’s authorship criteria, and no journal or funder formally defines “last author” as a role. It is an informal convention layered on top of the underlying authorship test — substantial contribution to conception, design, or data; drafting or critical revision; final approval; and accountability — which every listed author, regardless of position, must independently meet. See CASRAI’s Authorship entry and the ICMJE Authorship Criteria guide for that underlying test.

Last author vs. corresponding author

The last author and the corresponding author are often, but not always, the same person. Because the senior investigator frequently also handles submission logistics and post-publication correspondence, journals and readers sometimes conflate the two roles. They are formally distinct, however: corresponding authorship is a submission-and-communication responsibility assigned by the author group (see the Corresponding Author Responsibilities guide), while last-author position is purely a byline-order convention. A graduate student or postdoc who did the bulk of the writing and submission handling can be designated corresponding author while their supervisor remains listed last; equally, a senior investigator can be both last and corresponding author on the same paper. Bylines should not be read as self-explanatory without knowing which convention a given field, journal, or research group actually follows.

Why the convention varies by field

The “first author did the work, last author supervised it” reading is a discipline-specific norm, not a universal rule. It is strongest in biomedical and life-science research, where lab-based, hierarchical group structures are the norm. It does not hold the same way in fields that order authors alphabetically by surname regardless of contribution or seniority — mathematics, particle physics, and much of economics are the most commonly cited examples — where neither the first nor the last position carries any seniority or contribution signal at all. Some large, multi-institutional collaborations use their own group-specific listing conventions (for example, ordering by sub-team or contribution category) that don’t map onto either the ranked or alphabetical model. Anyone interpreting a byline — a hiring committee, a bibliometric tool, a co-author negotiating position — needs to know which convention actually applies to the venue and field in question before drawing conclusions from author order.

Making the contribution explicit instead of relying on position

Because byline position is an informal signal that varies by field and is easy to misread, CASRAI and NISO’s CRediT (Contributor Roles Taxonomy) — ANSI/NISO Z39.104-2022 — exists specifically to make each author’s actual contribution explicit rather than inferred from position. A senior investigator’s real contribution is more precisely captured through roles such as Conceptualization, Funding acquisition, and Supervision, alongside any other roles they actually performed. Journals that publish CRediT contribution statements alongside the byline let readers see who did what without having to guess from author order and field convention — a distinction that matters for authorship disputes, for research assessment exercises that increasingly discount raw byline position (see CASRAI’s coverage of responsible research assessment), and for early-career researchers whose non-first, non-last position can otherwise undersell a substantial contribution.

Illustrative examples

The following are illustrative composites, not real studies or named individuals.

• Typical biomedical pattern: A five-author lab paper lists a graduate student first (ran the experiments, drafted the manuscript) and the lab’s principal investigator last (designed the overall study, obtained the grant funding, supervised the work). The last-author convention correctly signals the PI’s supervisory role, even though “last author” itself is not an ICMJE criterion — the PI still had to independently meet the full authorship test.
• Alphabetical-order field: A three-author paper from a mathematics department lists authors purely alphabetically by surname. The last-listed author is not necessarily the senior researcher or supervisor — alphabetical convention carries no seniority signal, and readers familiar with the field know not to infer one.

Counter-example

A large multi-site consortium paper lists a site’s local investigator last as a courtesy convention specific to that consortium’s authorship policy, without that person having supervised the study overall (a separate, higher-level steering committee did). This illustrates why last-author position alone — without knowing the specific field, journal, or consortium convention in play — is an unreliable proxy for seniority or contribution, and why explicit CRediT statements are a more precise record than position alone.

Related terms

• First Author
• Corresponding Author
• Co-First Authorship
• Co-corresponding author convention
• Authorship