7 years ago, a mouse experiment was performed, and samples are still available for further analysis. This mouse experiment is already published with a certain readout. Now, we publish a whole different story, and one supplemental figure stems from the samples of that old experiment, with a new analysis. The new analysis was not performed by the experimenter of the mouse experiment 7 yrs ago. Still the experimenter is a co-author on the new manuscript. Is that valid? I always thought in such a case the paper should be cited in which that experiment was performed, and then of course the person who did the new analysis on the old samples should get co-authorship. But not the experimenter, since credits for performing that experiment were already gained in the other publication?

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    Do you know that the original author had no participation in the conceptual development of the new paper? In some fields a brief conversation with them might fully justify authorship.
    – Buffy
    Commented Apr 28, 2022 at 19:36
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    I'm confused. Who is suggesting she might be an author of the current paper? is it the original author? A supervisor? Or just a quandary in your group?
    – Buffy
    Commented Apr 28, 2022 at 19:53
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    Irrespective of ethical rules and proper authorship, see the answer of Peter Jansson, I strongly recommend not getting in to a fight with your supervisor. It leads nowhere good. Don't try to win the battle if it costs you the war.
    – Buffy
    Commented Apr 28, 2022 at 19:59
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    Was the raw data from the original experiment published alongside it?
    – Max
    Commented Apr 29, 2022 at 4:16
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    Just curious: if the given person is a good friend of your supervisor, how do you know they have not discussed topics related to the new paper? I am discussing ongoing research all the times with friends, and often have useful feedback from them. There are circumstances where I would consider coauthorship for signifficant, insightful discussion or idea from people who have never stepped in my lab (especially that it is free and zero effort on my side). Are you sure you want to die on this hill?
    – Greg
    Commented Apr 29, 2022 at 9:53

7 Answers 7


The co-authorship is not milk: there is no expiration date.

  • Controversial answer! On one hand, it is great when pithy answers cut through all the extraneous facts; on the other, it can be difficult to understand the reasoning. In any case, we will let the voters decide; please continue the discussion in the chat.
    – cag51
    Commented May 1, 2022 at 3:11
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    There is nothing controvercial here. Basic sanitaria. There is no need to explain why one needs to wash hands after each use of a bathroom, and do the explanation after each use.
    – markvs
    Commented May 1, 2022 at 4:23
  • It looks like you have made your decision and now use SE to justify it. Sorry, I cannot help. You are risking a lot. Is this paper worth it? Bye!
    – markvs
    Commented May 1, 2022 at 8:25

Data reuse is the norm in several fields and encouraged to replicate results and build on findings. Many journals require that data be made publicly available upon publication. It may also be a funding requirement. If all you are doing is reusing data from a previously published work, it would seem surprising that co-authorship could be expected.

Nature Data is an example of a journal whose sole purpose is the reuse of data. Obviously, co-authorship cannot be demanded from reusing data published here. In addition this stack academia question asks about co-authorship for data reuse with helpful responses with regards funding and data availability.

Whilst @markvs answer is both true and incredibly quotable, I would say building on or completing the unpublished work of somebody is not the same as building on their published work. In the first case, co-authorship would seem entirely fair; whilst citation would seem most fair in the second case.

However, I ultimately agree with what various people have said: it isn't worth getting into a fight over. It may be better to just get the PhD and use this as an 'annoying supervisor' story to swap with other academics. To paraphrase a great expression, 'annoying supervisor' stories are not milk: they have no-expiration date.

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    I would like to add that @markvs deserves to be cited for my joke at the end, but in my opinion does not deserve co-authorship of my answer. Commented Apr 29, 2022 at 9:17
  • "building on or completing the unpublished work of somebody is not the same as building on their published work" - this is exactly how I feel. I couldn't have phrased better what I actually want to say. Thanks, its good to hear that I'm not the only one thinking that way.
    – Amanda
    Commented Apr 29, 2022 at 10:55
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    But in this case the data does not seem to be reused from published work. the raw data was never published, but some observations/aspects about them were. So I think this might actually fall closer to using unpublished data than published. To quote one of the comments "The performance/establishment of the experiment is published. And how the samples (which we analyzed again for a different readout for the current study) were prepared." Commented Apr 29, 2022 at 15:20
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    Data reuse is something entirely different than the analysis of physical samples. Physical samples (by their vary nature) are in limited supply and cannot be made publicly available.
    – TimRias
    Commented Apr 29, 2022 at 15:31

While I think that authorship is not warranted in this case, you would be wise to submit (meekly) to your supervisor. The answer of Peter Jansson suggests why authorship is unlikely warranted.

But fighting with your supervisor over one paper isn't worth the pain it can cause if it spoils a relationship that you need to get your career started. There will be other, future, papers provided that you don't get sabotaged by a vindictive supervisor who seems to be exploiting students for an external friendship.

Protect your own long term interests. Live to fight another day. Sorry to have to say these things, but students have little recourse to such abuse.


I agree that this is a bit of a gray area. By the strictest definitions, it's quite possible they do not qualify for authorship. However, your supervisor thinks they do, and it really doesn't cost you anything to include them.

I also think you're likely underselling the contributions of the person who performed these experiments. Collecting data is...well, hard. Even when you are using well-reported basic techniques that seem to be used in labs everywhere, there is a lot of effort to bring any technique "in-house".

The person performing the experiments 7 years ago likely shaped how the data was recorded, the specific procedures undertaken, the choice of reagents and other materials. They may have made your entire project much easier than you realize. In a casual survey of other graduate students in biology, most of us agreed that all the data in our theses, collected over typically 5-6 years, probably could have been done in just 6 months if we had known what we were doing from the start. The other 4-5 years was just figuring it out and working out the kinks. All these things can be thought of as intellectual contributions that don't see the immediate link to your current paper, but your supervisor does. Just citing the older paper doesn't entirely capture the weight of these contributions. It's quite different if their work was done in another lab, and you're citing their overall methodology but still needing to do the work to replicate it in a different lab.

Authorship guidelines typically require authors to have some other contributions, though, besides just collecting data. At a minimum, they are expected to review and approve the final manuscript. My overall advice is that you should insist that they do this added step to be included as an author, rather than arguing they should not be an author by not providing them this opportunity.

It's also worth recognizing that in biology, there is no dilution of your work by including other authors. Often, the middle authors on a paper have made very minor contributions to the final work, limited to one figure of the paper, one verification step in the methods, etc, but nonetheless the paper would be incomplete without their addition. Having one more middle author will not reduce the "credit" you get for publishing the paper as first author.

  • The supplemental figure seemed to require the existing samples prepared by the former student ( so it seems to me the the supplemental figure was not based simply on reanalysis of public data in prior paper.) I assume that asking some other group to send their old samples for reanalysis would include discussion of co-authorship.
    – Carol
    Commented Apr 29, 2022 at 16:57
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    In any case, does the OP want an advisor who supports crediting her former group members when the group uses their samples or not? When OP leaves there also will be projects where he has left samples or results that may be further tweaked into minor supporting pieces in future group pubs. Just because a group member leaves and the current members don't remember him isn't a reason to treat his old samples as 'public domain' within the group. I think the advisor is showing by example how to do things right. (+1 @BryanKrause answer because it notes that the OP is underselling the prior work)
    – Carol
    Commented Apr 29, 2022 at 17:23
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    This answer hits all the points: the question author is unlikely to be able to judge objectively, they lose very little from acquiescing, fighting with their supervisor over a questionable issue will sour relations necessarily, and, critically, mouse work is really hard and should not be undersold.
    – Ian
    Commented Apr 29, 2022 at 19:13
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    I do not know where you get the assumption from that I underestimate mouse work and do not appreciate the work done.
    – Amanda
    Commented Apr 30, 2022 at 6:07
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    +1 for pointing out that it can be very hard to judge "old" intellectual contributions. In particular, someone may do an experiment as part of their project and as a side line develop an idea of an additional line of research which may be followed with those samples or data. Thus having an intellectual contribution to the outline of a project that someone else get to work on years later. This would be one scenario where OP doesn't know about an intellectual contribution that has actually happened, but their supervisor does.
    – cbeleites
    Commented May 1, 2022 at 12:23

One way to view this issue is to apply the "Vancouver rules" (e.g. as described by the ICMJE, International Committee of Medical Journal Editors. These recommendations outline what is required to become a co-author on a scientific manuscript. Note the "AND" in the list of requirements. It is clear that not all agree with these recommendations but it is also clear that authorship is given for the wrong reasons in many cases. In your case the authorship could be considered a "honorary or guest authorship" (COPE, Council of Scientific Editors) but would be perfectly normal if the person(s) fulfil(s) the expectations of an author, i.e. provides some intellectual input to the work to be published.

So in the end the case may seem clear but not easy to resolve if co-authors do not agree on the rules.

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    okay I understand that. But in my case, she did not give any intellectual input. But I am sure that the corresponding author and my supervisor who put this person on the paper, would just claim she gave intellectual input. So it seems like I can only lose here? I always thought there would be specific guidelines for such cases (as citing the paper with the previous experiment and then acknowledging the person, or sth similar)
    – Amanda
    Commented Apr 28, 2022 at 20:02
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    Here, would it have been appropriate to give that person the opportunity to fulfill these roles? It is tricky to use the criteria of contributing to the manuscript if the person was not allowed the opportunity to contribute to the manuscript.
    – Dawn
    Commented Apr 28, 2022 at 20:24
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    @Amanda, Please read and try to understand the underlying message of the links I provide. Being a "fan" or not is not an issue, it is whether or not you think the recommendations should be be followed or not from an ethical perspctive that counts. It IS an ethical question in the end. Commented Apr 28, 2022 at 23:39
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    @Dawn indeed, the ICMJE rules say that if someone would qualify for authorship under other criteria they must be given the opportunity to meet those related to contributing to and revising the manuscript.
    – rhialto
    Commented Apr 29, 2022 at 7:12
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    The ICME rules are terrible and deny junior scientists just contribution for their work. No-one should be using or promoting them. Commented Apr 29, 2022 at 7:25

recontextualizing the problem

Let's say there are three researchers, Alice, Bob and, Carol. Bob and Carol each design experiments about how a treatment affects mice. They are looking at two aspects of the same treatment, so the control and treatment groups are the same. Bob's experiment uses lung tissue, and Carol's uses brain tissue. Alice is an expert in running this treatment protocol, so she deals with the mice and collects all of the tissue samples. She gives the appropriate samples to Bob and Carol and lets them take over from there.

Bob and Carol each do the rest of their experiments totally on their own with no collaboration from anyone (even each other). Then each writes a paper. At this point I think most people would argue that Alice deserves to be a co-author on both papers, due to her direct contribution. It doesn't matter if the samples Alice collected sat in a freezer one night or one week or one year. Alice's work was instrumental to Bob and Carol completing their experiments.

In another scenario Bob doesn't exist. Anything Bob would have done, Alice did. Most people would argue that Alice still gets to be a co-author on Carol's paper, due to her direct contribution. If those samples Alice collected didn't exist, Carol couldn't have gotten started.

Different fields have different standards of authorship, and different individuals have different ideas of how one meets those standards. People disagree about these things all the time. In this case I think it helps to look at things from Alice's perspective. In my own work I tend to err on the side of inclusivity, when disagreements arise. In the end it will make no difference to your career if you are first author on a paper with five co-authors or a paper with six.

  • Well in this scenario I agree. But: in my case the situation is different. They publish as you describe. Then a fourth person, lets name her Karen, takes the lung tissue, analyzes it for a different readout/idea, and publishes that. Who of the other three authors gets co-authorship on Karen's paper?
    – Amanda
    Commented Apr 29, 2022 at 21:42
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    I don't really understand why your situation is significantly different to the first one with Alice, Bob, and Carol. I'd still say Alice deserves credit. And possibly Bob (depending on what was done to the tissue)
    – DavidW
    Commented Apr 30, 2022 at 7:44

If you are feeling pressure to include the original author as an author of your paper and you are considering going along with it, one way to handle the ethics is to actually reach out to that author for collaboration. If they provide even a minor academic contribution (i.e. other than assistance that is purely clerical or administrative), you may be ethically obligated to include them as an author.

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