Authorship Order

The order authors are listed on peer-reviewed scientific papers serves as a shorthand that signifies the contribution of each author. Each discipline has its own system in terms of what each authorship position signifies. Here I write from the perspective of the basic biomedical sciences.

What Each Position Signifies

The last author is the corresponding author. It is almost always the PI that heads the lab where the bulk of the research presented in the paper occurred. The corresponding author's email is listed on the paper as they are responsible for answering questions and managing data and reagent distribution. It is possible for a paper to have multiple corresponding authors.

The first author is usually the grad student, postdoc, or other scientist in the corresponding author's lab that performed the majority of the experiments presented in the paper.  The first author is also almost always the primary writer of the paper. While all authors are technically responsible for the veracity of the data in the paper, the corresponding author, along with the first author, are commonly considered primarily responsible. After the first author people are arranged in order of decreasing contribution to the paper.

Sometimes two people contribute at the same level. In this case, they can be co-first authors. Journals indicate co-authorship with an asterisk or star next to both names and a footnote. While both of these people are first authors, their names should always be presented as printed on the paper; do not swap the order.

All journals post their criteria for authorship on their website. Criteria include generating or analyzing data, writing the manuscript, planning experiments, generating reagents, and contributing hypotheses or ideas. Anyone that meets these criteria should be included as an author. If someone contributed, but not enough to meet the criterion for authorship (a distinction that is both lab and field specific), they are usually named in the acknowledgements.

Does authorship order matter? 

The answer to this, like many questions, is that it depends. Having first author papers is a de facto requirement for a successful graduate and postdoc. The more first author papers a trainee has, the more successful they are considered to be. Corresponding authorships work the same way for PIs. They're required for tenure at US R01 (and often R02 and R03) level universities, for grants, and generally to show ownership of a concept or a body of research.

Middle authorships are also important. They demonstrate that the author is someone willing to use their skills, expertise, and time to advance someone else's project. Middle authorships also show that the author’s skills are valuable outside their specific field of interest. Scientists without middle author papers may be assumed to be difficult to work with.

What can you do if you feel you have been treated unfairly? 

Whenever deciding to contest an authorship decision, it's worth thinking through the possible outcomes and ramifications of contesting the authorship order. Is it worth upsetting a colleague over the issue? How important is the authorship order to each of you? How certain are you that you are correct?

As a first step, write down, objectively, all that you contributed to the paper and why this leads you to conclude that there was an error in the authorship order. It also serves as a method for you to understand everyone's contributions with a bit of objectivity and assess their importance to the paper. For example, people often leave unfinished 1st author papers when they move on from a lab. It is not uncommon for a co-first authorship to be awarded to the student or postdoc who finished the abandoned work, gets it submitted, and handles the reviews. While the original first author may technically have done more, the paper would not have happened without the second first author stepping in.

If writing out your argument doesn’t provide clarity, ask the corresponding author how the authorship decision was made. Do this in the most non confrontational way you can, and approach the conversation with curiosity. Their response may provide you with an opportunity to clarify incorrect assumptions.

If you still feel strongly that you have been slighted and aren’t getting anywhere working with the corresponding author, you can appeal to a colleague or to the journal directly. Be sure that you are right and that it is critically important to contest the authorship because, no matter what the outcome, this action will hurt people’s feelings and have repercussions. In addition to being "right" you also must be sure that you have an airtight case, as the bad feelings will not disappear if the journal finds against you. If you are a PI yourself you should explain the scenario to your peers and your chair to get their advice before proceeding. If you’re a trainee collaborating with another PI, you should have your PI bring the contest on your behalf.

Final Thoughts

Throughout your scientific career, people will approach you with all sorts of ideas and requests. Some will lead to authorships, some to acknowledgements, and some simply to a thank you. While publications are the currency of academic science, collaborations have rewards beyond authorship. Take the long view when things don’t go your way.