Who Goes Where? Understanding Authorship Order in Chemistry

Authorship can be surprisingly confusing when students first start reading and writing scientific papers. A manuscript may have three authors or thirty, and the order of those names is rarely accidental. To someone new to research, however, it is not always obvious what being the first, middle, last, or corresponding author actually means.

Unfortunately, there is no universal rulebook that applies perfectly across every scientific discipline or even every research group. Authorship conventions can vary. In chemistry and many related biomedical sciences, though, there are some common patterns that are helpful for students to understand.

First Author

The first author is typically the person who performed the largest portion of the research and took the primary role in writing the manuscript.

For an undergraduate researcher, becoming first author generally means doing much more than completing a few experiments. The student may have helped develop the project, performed a substantial portion of the experiments, analyzed the data, created figures, worked through multiple failed experiments, and participated heavily in writing and revising the manuscript.

That last part is important. Students sometimes assume that the person who performed the most experiments automatically becomes first author. Experimental work matters enormously, but manuscripts also require data analysis, interpretation, figure preparation, writing, revision, and responding to reviewers. First authorship usually reflects the overall contribution to bringing the project from experiments to publication.

Last Author

The last author is typically the principal investigator, commonly abbreviated as the PI.

The PI is the researcher who leads the laboratory or research group and has overall responsibility for the project. The PI may develop the original research question, obtain funding, supervise students, provide laboratory resources, help troubleshoot experiments, interpret results, and guide the manuscript through publication.

Importantly, being the last author does not mean that person contributed the least. Quite the opposite. In many chemistry and biomedical research fields, the last-author position signifies leadership of the research group.

This is one of those conventions that can be especially confusing for students. When reading a paper for the first time, it is tempting to assume that author order simply goes from “most important” to “least important.” Scientific authorship does not really work that way.

What About Everyone in the Middle?

Middle authors generally contributed meaningfully to the project but did not have the same overall role as the first author or PI.

Those contributions can vary dramatically. One researcher might have developed an analytical method. Another might have performed a specialized experiment. Someone else might have completed statistical analysis, provided important samples, or helped interpret the data.

This is one reason authorship order can become difficult.

Imagine a project where one student performs most of the cell culture experiments, another performs all of the microscopy, and a third completes the statistical analysis and produces the figures. How exactly should those contributions be ranked?

There is not always an obvious answer.

Ideally, authorship expectations should be discussed early in a project and revisited as the project develops. Contributions change. The student initially expected to be first author may graduate before the project is completed, while another researcher may take over the experiments and manuscript preparation.

Authorship should reflect what actually happened, not simply what was planned at the beginning.

The Corresponding Author

You may also notice a small symbol, usually an asterisk, next to one author's name. This typically identifies the corresponding author.

The corresponding author serves as the primary contact for the manuscript. During publication, this person usually communicates with the journal, submits the manuscript, receives reviewer comments, and coordinates revisions.

After publication, the corresponding author is also the person readers should generally contact with questions about the study.

The corresponding author is often the PI, although that does not necessarily have to be the case. Some manuscripts also identify more than one corresponding author.

Authorship Order Does Not Tell the Whole Story

One of the problems with traditional authorship is that a list of names does not tell you what each person actually did.

Consider a paper with six authors:

Smith, Jones, Patel, Nguyen, Garcia, and Lee.

Smith is probably the primary researcher. Lee may be the PI. But what did Jones, Patel, Nguyen, and Garcia contribute?

That information historically has been difficult to determine from the author list alone.

This is where the CRediT Contributor Role Taxonomy becomes particularly useful.

CRediT provides a standardized system for describing individual contributions to a research project. Rather than simply listing authors, researchers can specify the roles each person performed. The taxonomy contains 14 contributor roles, including conceptualization, data curation, formal analysis, funding acquisition, investigation, methodology, project administration, resources, software, supervision, validation, visualization, writing the original draft, and writing through review and editing.

A contribution statement might therefore show that:

• Student A performed the investigation, formal analysis, visualization, and original manuscript drafting.
• Student B contributed methodology and validation.
• Student C contributed data analysis and manuscript editing.
• The PI contributed conceptualization, funding acquisition, supervision, project administration, and manuscript editing.

Suddenly, the author list tells us much more about how the research was actually completed.

CRediT was developed specifically to complement traditional authorship by providing a structured description of the different contributions behind research publications. It was approved as an ANSI/NISO standard in 2022 and is now used by many journals and publishers.

Why This Matters for Students

Authorship can feel mysterious to undergraduate researchers because students are learning two things at once.

First, they are learning how research works.

Second, they are learning how the scientific community communicates who was responsible for that research.

When reading papers, students should begin looking beyond just the first author's name. Look at the final author. Identify the corresponding author. If the journal provides a contributor statement, read it.

When writing papers, students should also begin thinking about their own contributions in these terms.

Did you perform the experiments?

Did you design the methodology?

Did you analyze the data?

Did you create the figures?

Did you write portions of the manuscript?

Did you help revise the manuscript?

These activities are all part of producing research.

CRediT provides a particularly useful framework for having those conversations because authorship becomes less about asking, “Where should my name go?” and more about asking, “What did I contribute to this project?”

That is ultimately a much better way to think about scientific authorship.

This is free, always will be — but if you want to say thanks, a chai latte tip is always appreciated ☕

Venmo @Jessica-Pullan