I'm a postdoc in computational biology. I've been given the opportunity to choose if I want to be co-first author (listed second) or a co-corresponding author (possibly listed next-to-last or third from last) on a manuscript based on my contributions. It has been beaten into my head that postdocs looking for a job are judged by their first author publications, but I've also recently heard that having corresponding author papers highlights your ability to plan and supervise a study and may help you get a job. Which option is better and why? I'm already listed on a separate manuscript as the last (and co-corresponding) author.
I would say co-first author:
- First authorship is more important: if a professor both led the work and made the biggest contribution to the paper, they will generally choose first authorship rather than last authorship.
- Early in your career, making a big contribution to the research itself is likely to be most important, and first authorship shows that.
- The "last author" signifying the leader of the work is less widespread (one discussion here). Even in fields that use this convention, it is not always used. Thus, your last authorship might not mean as much. Especially if someone knows you are not a professor leading your own lab, they might not give you much credit for this.
- "co-first authorship" is a clear idea: you are one of two people who equally made the largest contributions to the work. But "co-last authorship" is not so clear. What does it mean? Especially if the other last author is the professor who runs the lab? It's not clear what this would say about your contribution.
Of course this is referring to fields where authorship ranking by contribution is used; this isn't universal.
If possible, you should aim to have both in your portfolio. Your goal as a postdoc is to show that you are as versatile and as talented as possible. First-author publications demonstrate your ability to do research; "last-author" or corresponding author publications show an ability to oversee research (although the former effect is stronger than the latter).