In my field (theoretical computer science), authors of any paper are always listed alphabetically; our papers don't have "first authors". (Well... hardly ever.) In most other disciplines, at least within science and engineering, the ordering of authors is a signal about their relative contributions to the paper, with the first author indicating the most significant contributor. Hiring and promotion committees do give extra weight to "first-author papers" (and sometimes have to be reminded that not all areas have them). As an outsider, I find this practice confusing.

What does first authorship actually mean in your discipline? I understand vaguely that the first author is supposed to be the one who "did the most work", but what counts as "work" in this comparison? Does "most" mean "more than all the other coauthors together" or just "more than any other coauthor"? What happens when the comparison is unclear? How often is "did the most work" the actual truth, versus a cover story for a more complex political decision?

I realize that the precise answer is different for every paper. I'm looking for general guidelines for how an outsider (like me) should interpret first authorship in your field. Pointers to guidelines from journals or professional societies would be especially helpful.

Please give only one answer per discipline.

Answer list:

  • 8
    It's a "community wiki"; no best answer should be chosen, given the nature of the question.
    – aeismail
    Commented Mar 12, 2013 at 9:57
  • I am in the field of Occupational Therapy. Does anybody have an answer for this question in my field? I am a recent graduate. Thanks! Karina
    – karina
    Commented Jun 1, 2013 at 20:40
  • 1
    You may want to look at Information-theoretic author order for a thorough treatment of this question. Commented Jun 12, 2014 at 3:52
  • 3
    I must say that most of the answers don't say what first-authorship really means, but rather what it ostensibly means, which is not the same thing.
    – einpoklum
    Commented Oct 8, 2014 at 22:02
  • I think engineering should be included in the list of 'where order matters'
    – user67275
    Commented Feb 9, 2023 at 1:41

18 Answers 18


Pure Mathematics: All authors are assumed to have contributed equally and are listed alphabetically. The American Mathematical Society has put out a statement to this effect.

  • 18
    Yep. Theoretical computer science inherited this attitude from math.
    – JeffE
    Commented Jul 16, 2012 at 4:59
  • 10
    +1 for the link. I know this is the standard, but I didn't realize that the AMS had issued an official statement to that effect.
    – Dan C
    Commented Jul 16, 2012 at 5:09
  • 8
    Since theoretical computer science is a branch of mathematics, you can legitimately point young theorists to the AMS statement. </soapbox> But I agree that SIGACT should post an official "same here".
    – JeffE
    Commented Jul 16, 2012 at 23:21
  • 11
    All authors are assumed to have contributed equally –– I always thought Mathematicians make sensible assumptions, or even provable ones.
    – Walter
    Commented Jun 21, 2017 at 9:21
  • 10
    I guess I'd also say it's not really that people believe the contributions were truly equal; rather, the authors reject the notion that their contributions can be strictly ordered. Commented Nov 24, 2021 at 0:57

Cognitive neuroscience. The first author (most of the time a PhD student or a post-doc) is typically involved in designing the experiment, running it, analyzing data and writing up. The other authors are mostly involved in some but not all of these steps. They will usually help out but not do all of the work (e.g. they might show the first author how to do some analyses, or they might make many useful comments on a draft of the manuscript). In the institute where I'm studying (in The Netherlands), all the papers where I am first author will also be chapters in my thesis, and all the unpublished chapters in my thesis could potentially become papers where I am first author. Those where I am only partly involved will be a chapter in someone else's thesis, and I will not be first author.

The last author is as important as the first one. It is typically the supervisor, and ideally the supervisor is heavily involved. In labs that grow too big, a post-doc (once trained by the supervisor) might take over this role, but the last authorship still goes to the supervisor. It's like a brand name, it tells you whose lab the work is coming from. If you know a bit about the field, you will know the general ideas the paper will revolve around. If two supervisors are involved, they have to work out whose name will be last. I know of one situation where the two believed in different outcomes of the experiment, and decided beforehand that the person who turns out to be right will get last authorship. Most of the time, though, the decision is based on who did more supervision, which is ideally agreed on beforehand.

  • I think a common but unfortunate way to see the ordering in biomedical sciences is: First author = the person who did the most work, including writing the paper; Last author = the one who paid (and often, but not always, supervised the project to some degree) for the work by means of instrument, time and lab-space. Shared first-authorships happen on some journals that admit it, however not so common perhaps
    – posdef
    Commented Mar 12, 2013 at 9:27
  • 6
    This convention also applies to psychology more generally. Commented Aug 7, 2015 at 7:27

Computer Science. Computer science varies by field:

  • Theoretical computer science generally follows the same conventions as mathematics: the ordering of authors is alphabetical. Cryptography follows the same conventions.

  • In programming languages, computer systems (e.g., operating systems, databases, computer security, etc.) and other applied fields, the order of the authors is significant. The authors are often listed in order of decreasing contribution; faculty or senior folks are typically listed last. The first author often has led the design, implementation, and experiments presented in the paper or has contributed the most to these elements. Other authors may have contributed more in total, or even individually, to these components, but sometimes at the direction of the lead author. The lead author may also have been considered to be primarily responsible for the writing of the paper, though not always.

    In cases where the lead is shared between several people, papers can have multiple "first" authors, listed alphabetically, followed by an alphabetical listing of the other junior authors, followed by the senior authors. I have seen this fact listed explicitly on a CV. Usually, a PI comes last even if he or she provided the bulk of the leadership of the project; a PI coming first is indicative of an unusually high level of contribution from the PI / low level of contribution from the junior authors.

    Overall, the meaning of first authorship ends up being vague enough that usually you have to explain the level of contribution explicitly in reference letters as such.

  • HCI (human-computer interaction) follows similar conventions to those in computer systems. The authors are listed in decreasing order of contribution. The first author is generally the person who both had the "main idea" and led the effort to ensure that the efforts to carry out the research and write the paper occurred properly. The authors are generally then decreasing in order of their contribution.

  • 4
    What does "theoretical computer science" exactly mean? I'm a PhD student in programming languages and even at POPL (our most theoretical conference) first authorship counts. Commented Oct 11, 2013 at 22:39
  • 2
    These observations follow my own experience. However, it should be noted that some professors (and, hence, their students and postdocs) use alphabetical ordering despite being in a generally 'in order of contribution' field. In my experience it's usually profs whose names start with [A-C] that seem to be keen on this :D anyway, the practical confusion is small, as those professors are well-known in my field.
    – xLeitix
    Commented Dec 22, 2013 at 13:32
  • 3
    Another comment: JeffE asked various times how 'most contribution' is defined if different people contributed to different aspects of the project. In computer systems / software engineering, this is mostly a non-issue. Basically all projects are concepted, executed, and written up by a single person (often a PhD student, and the first author). For the remaining authors, the ordering can get a bit muddy, but nobody really cares whether they are 2nd or 4th author.
    – xLeitix
    Commented Dec 22, 2013 at 13:36
  • 2
    @xLeitix: Umm, I wouldn't say that all projects are the work of one person. Not in Academia and especially not in industry.
    – einpoklum
    Commented Oct 8, 2014 at 21:58
  • 6
    Very late to the question, but the answer to Blaisorblade's query is that this is referring to combinatorics, algorithms, graph theory, complexity theory, computability theory, and related topics which are commonly collectively referred to as "theoretical computer science" or "theory of computing." This is distinct from "the most theoretical topics in each field across CS." Big-name conferences in this field include STOC, FOCS, and SODA Commented Sep 7, 2018 at 21:12

Medicine: The first author is the author. He or she is credited with the bulk of the work, and some even consider first authorship to be the only authorship of value. This may be partly due to the fact that a medicinal paper often has many authors, with some having done next to nothing for the paper (maybe read it). Although journals would like to discourage this, people write their colleagues' names on their papers, so maybe their colleagues will do the same for them and both get a more impressive publication record.

Sometimes you see asterisks above the first two authors' names, indicating that "both authors contributed equally", although it seems to me that this is in general not well recognized. I've been told journals want one main author. Also, for many academic positions a given number of publications is required, with some minimum number first authorships.

  • 4
    Biomedical engineering matches this description, too.
    – user244795
    Commented Jul 26, 2012 at 12:31
  • 3
    This is essentially also true for Epidemiology
    – Fomite
    Commented Mar 12, 2013 at 1:17
  • 8
    I believe this applies, more or less, to all biomedical sciences
    – posdef
    Commented Mar 12, 2013 at 9:22
  • 2
    "with some having done next to nothing for the paper" - Eh, in my experience often these limited contributions are from other physicians who enrolled patients. They often have had a medical role in the study even if they didn't have a design/analysis/writing role. Journals have begun to discourage this, though.
    – Bryan Krause
    Commented Jul 30, 2021 at 20:32

Applied mathematics. The first author is usually the one who contributed the most. However, sometimes the pure mathematics convention of alphabetical ordering is used; this may be expressly declared in a footnote. There are no official guidelines from SIAM.

There is no significance to being the last author, and only those who contribute substantially are listed as authors. If not directly involved in performing the research and writing the paper, the supervisor is typically only listed in the acknowledgments.

  • 11
    Again, what does "contributed the most" actually mean? The most text? The most code? The most ideas? The most proofs? The most analysis? The most graphs? All of the above?
    – JeffE
    Commented Jul 16, 2012 at 23:23
  • 13
    @JeffE there is no generally agreed-upon metric. Commented Jul 17, 2012 at 14:24
  • 8
    @DavidKetcheson obviously describes an 'applied maths' community completely different from mine - I'd be hard pressed to name a single paper in my version of 'applied maths' that doesn't stick to alphabetical order. His 'usually' certainly doesn't apply to the applied-math community that I'm part of. And we never discuss that in a footnote. 'Applied maths' seems to be a big place ... Commented Apr 2, 2014 at 20:23
  • 4
    @MarkPeletier I am very curious, so I looked at publications listed on your webpage. They seem to strongly contradict your comment -- for instance, on win.tue.nl/~mpeletie/Research/PubsElastics.shtml, every multi-author paper violates alphabetical ordering. I'm not saying you're wrong -- I haven't looked at all of your publications, by any means. But I think if you leaf through most SIAM journal issues, you'll see lots of non-alphabetical orderings too. Commented Apr 3, 2014 at 16:22
  • 7
    @DavidKetcheson Looking through my own list of publications, I now see the general pattern: much of my work is with non-mathematicians, even when published in SIAM journals, for instance (since you mention those). In such collaborations alphabetical order usually doesn't win (despite my attempts :-). But when publishing only with (applied) mathematicians, the order is invariably alphabetical. Commented Apr 5, 2014 at 21:02

Engineering: A first author is usually the lead student or worker on the particular project from which the paper originates. If there are multiple people working on a common project, then the authorship goes to the person whose results are most prominently featured, and who has done the most work in preparing the manuscript for publication.

A significant exception might be in multi-part papers, in which the first authorships may be shared among different people to recognize equality of contributions throughout the combined work.

The last author is often a professor, who advised or directed the lead author, but may have done little work on the project themselves.

  • 6
    But what does "lead student" mean in this context? Specifically, what happens if the student whose work is most prominent and the student who did the most writing are different?
    – JeffE
    Commented Jul 16, 2012 at 23:17
  • Or does that really never happen?
    – JeffE
    Commented Jul 16, 2012 at 23:24
  • 9
    This has happened twice in my career. In one case, the PI was the lead in the work, but I was the primary writer. So he took the last position and offered me the first position. In another, I was the main writer, but not the primary worker; in this case, I ended up second on the authorship list. But, in general, I think this is a relatively rare event, particularly at the graduate school level. (This may occur more often when everybody is "staff-level.")
    – aeismail
    Commented Jul 17, 2012 at 4:33
  • "first authorships may be shared among different people", how this may happen when we see the names appear in order, I mean, one name comes sooner, then the second, then the third… I have never seen two names as first authors on the papers, for instance.
    – enthu
    Commented Nov 1, 2021 at 15:18
  • @enthu While still relatively rare in engineering, in biomedical fields it is done with a special designation in the author list. In some areas, it is so common that it is included in the journal submission forms, and the designations are applied automatically by the system.
    – jakebeal
    Commented Nov 2, 2021 at 1:09

Chemistry: similar to cognitive neuroscience and microbiology and many other fields - the first author is usually the individual who put most of the labor into the work. The PI, usually the last author, may have come up with the idea, but the first author usually does most of the following work: designing the experiments, synthesizing and purifying the compounds, collecting and analyzing the data, and writing the paper. The other authors might be: A student in a collaborating group that conducts an important, specialized experiment for the first author, a junior student in group who prepared some of the intermediates and collected routine data to help the first author and to learn the workings of the group, or a consulting professor offering expertise in an area that the first author and PI are weak in. The last author is usually the PI.

Some journals are beginning to ask for specific descriptions of the contributions of each author to combat vanity authorships. You also occasionally see the note that two or more authors may have contributed equally, but some journals discourage this practice also. As an example of this sort of declaration, the following statement was attached to the final article from my thesis:

Author Contributions

B.N.N. and S.Z. were coequal in their contributions and should both be considered first authors. B.N.N., T.Y.M., and G.R.H. proposed the project and designed the experiments. B.N.N., S.Z., J.T.A., and P.C.M. performed the synthesis and characterization. C.M.C. and G.R.H carried out the calculations. B.N.N., S.Z., T.Y.M., and G.R.H. assembled the data and wrote the manuscript.

Historically, the practice of putting the PI last is relatively recent. The PI used to be listed first, so that the PI was easier to identify and the collective works of the PI were easier to find in printed catalogs systems (where articles wee often indexed by the first listed author only). The historic order would have thus been: PI, first author, second author, etc. The advent of electronic databases removes the need for the PI to go first, though there are some who still do it that way.

  • 9
    "Coequal"??????? Commented May 5, 2014 at 3:07

Microbiology: Similar to cognitive neuroscience: Ph.D student is first author by virtue of having done most of the work, and the PI is the last author. If it is agreed upon that more than one person did "first-author-level" work, then the authors are listed alphabetically with a footnote noting this fact on the title page.

  • 8
    Does every paper in microbiology really have most of the work done by a PhD student? Commented May 29, 2013 at 4:08
  • 1
    No, certainly not! The first author is often a post-doc (if they are the person who did the bulk of the work). As they move up the food chain, they might have several PhD students/assistants/other students working under them who do the hard work in the laboratory under their guidance - then they would typically move towards a more senior author position. Occasionally a PhD student or post-doc does 90% of the work and leaves science without writing up their research - then a lucky student or new postdoc may get to write it up and claim pole position. There's diversity out there... Commented Feb 2, 2018 at 16:14

Epidemiology: First author generally means the author who did the bulk of the writing, and is likely directly responsible for the analysis of the data. The last author is (often but not always) the project's PI, a senior member if its a multi-site collaboration, or a place where someone who contributed heavily in some aspect, but not as much as the first author, goes.

Generally speaking, first authorship is considered the most important, last authorship has some benefit in terms of establishing a mentor role or the concept of the author as a senior researcher.

The exception for this is a small number of "pairs" of methodologists who tend to write papers together, which end up getting seen as a kind of equal contributors.


Biology: I felt the answers for medicine, microbiology, and epidemiology may not give the complete picture. Of course this is my own opinion, as there are no real formal rules.

The unofficial rules: In biology, the first author is the person whose contribution is larger than that of any other author. It is cannot be the author that contributed more than the combined contribution of all other authors - this definition doesn't even work mathematically (a 25%/35%/40% contribution paper would have no first author).

However, the situation is more complicated. Usually, the subsequent order of authors is according to decreasing contribution. Also, at the end of the authors list the scenario is mirrored: The last author is the senior author (i.e. the PI) that contributed the most, with the order of senior authors again reflecting their contribution (mirrored).

Then, it gets even more complicated. In some cases, you can have co-first authors. This is usually marked by the journal, indicating that these authors had equal contribution. Then, there is the "corresponding author" mark. Some (but this is less widely accepted) use this is to signify equal contribution of the senior authors, so for example you would mark both last 2 authors as "corresponding authors".

Practical issues: While it may seem to be silly to people not used to this method, the order of authors is actually quite important. For graduate students and postdocs, fellowships and prizes will often only consider your first-author papers as your "real" papers - this is usually written in the rules (you may asked to list only first-author papers). Furthermore, if you are co-first (equal contribution), you will often be required to detail your exact contribution (sometimes your supervisor needs to detail it as well in these cases). For PIs, the situation is similar - funding agencies will often only consider your last author papers.

Another less important issue is association with the paper. A paper will be generally referred to by the first author's name, e.g. "Smith et al.". If you are the first author you will be immediately associated with the paper. If your paper is high-impact, there can be benefits to this in terms of establishing your name in the field. This is one reason why even "equal contribution" may not be considered really equal by some.

Biology vs. other disciplines: Finally, I want to explain why this practice might be useful in biology and how it is different than math or CS, for example. First, any graduate student or postdoc is always under supervision. It is customary that regardless of the actual amount of involvement of the supervisor in a project, the supervisor is always listed as the senior author. You have to remember that it is quite rare for PIs in experimental labs to actually do any actual work themselves (this is different from theorists). This is not to say they cannot be highly involved. Then, many projects are collaborations between multiple research groups. It is very common to see 15-20 authors on a paper, and recently there have been many papers published by research consortiums, having hundreds of authors (although in that case the order of the author list is slightly different). One author could really be doing much more work that some other author, which is on the paper just because he/she contributed some biological sample or ran some program.

Is it good? I don't think this system is optimal. It can lead to personal conflicts and affect people's careers. Some journals try to bypass this system by adding a section detailing the individual contribution of each author, but this isn't widely recognized. Some funding agencies ask you to quantitatively mark the contribution in percentage of each author - but how do you do that? It is extremely difficult to quantify. One author spent a lot of time doing experiments, and another spent a lot of time analyzing the results - who should be first? It is very subjective and in the end is often settled by politics.

  • Replace "bypass this system" by "move this system to someplace else in the paper"...
    – einpoklum
    Commented Oct 8, 2014 at 22:00
  • @einpoklum I think they can potentially be more helpful, since they give more details on what each person did, and do not define how important each part is. Ideally, readers could decide for themselves how to weigh the importance of each part.
    – Bitwise
    Commented Oct 9, 2014 at 14:16
  • What you suggest is actually what is being done in these "Contribution" sections. The only problem is that the journals still keep the authorship order and that is the main thing people look at. The problem is not the journals, but that the whole system works this way - most evaluations (career, funding) attribute high importance to this order.
    – Bitwise
    Commented Oct 9, 2014 at 14:27
  • So people need to have the courage to be the first to switch to alphabetical, and indicate that is the order they're using. I know it's easy for me to preach, but it's still what I think could be the way.
    – einpoklum
    Commented Oct 9, 2014 at 15:05
  • 1
    @einpoklum it has to start from the top (funding agencies, academic institution policies, top scientists), I think. If someone at the early stages of their career say they don't care about author order, most chances they just won't have a career.
    – Bitwise
    Commented Oct 9, 2014 at 15:59

Chemical Engineering: The first author is generally considered as the main contributor. In case there are multiple students who made equal contributions, then this is specified as such in the list of authors. (Mostly by adding an asterisk on the names and a footnote explaining the asterisk). Certain groups follow a policy of Adviser first and then rest, though it is considered as arrogant (This is prevalent in mostly Chemistry related sub fields).

In Machine Learning/Applied Computer Science the policy is again similar as Chemical Engineering with Student first and Adviser last, if there are multiple advisers then the advisers tend to rotate between different papers from the same project.

Finally in Medicine especially in General Medical journals, There is a detailed statement of contributions.

E.g. Author Contributions: Dr De Wals had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: De Wals, Deceuninck, Toth, Boulianne, Landry, De Serres. Acquisition of data: Deceuninck, Toth, Boulianne.

Analysis and interpretation of data: De Wals, Deceuninck, Brunet, Boucher, De Serres.

Drafting of the manuscript: De Wals, Deceuninck.

Critical revision of the manuscript for important intellectual content: De Wals, Deceuninck, Toth, Boulianne, Brunet, Boucher, Landry, De Serres.

Statistical analysis: Deceuninck. Obtained funding: De Wals, Boulianne, De Serres. Administrative, technical, or material support: De Wals, Deceuninck, Toth, Boulianne, Landry.

Study supervision: De Wals, De Serres.

Another important point is how are paper cited, from what I remember esp. in chemical engineering. A paper is generally mentioned as Last_name et al. and if there are only two authors or two equally contributing authors then it is mentioned as Last_name_1 & Last_name_2 et. al or just Last_name_1 & Last_name_2.

  • 1
    Just to clarify (I stumbled a bit): last name = surname, not about the order of the author list: Last_name_of_first_author et. al.
    – cbeleites
    Commented Jul 17, 2012 at 7:56

Computer Science This really depends on the institution and the group. In one group I've been working in the ordering was always alphabetical and doing otherwise would have been considered impolite. In another group, the PhD-first-boss-last principle was used.

  • 2
    And if there was more than one PhD student involved? (Or for that matter, more than one "boss"?)
    – JeffE
    Commented Jul 16, 2012 at 23:18
  • 1
    Then it would depend on their respective contributions, or it will be done alphabetically. Commented Jul 17, 2012 at 0:26
  • 2
    Then how do you tell whether a given paper's authors are alphabetical because they're equal, versus alphabetical because the alphabet happens to agree with contribution rank?
    – JeffE
    Commented Jul 17, 2012 at 1:16
  • 7
    Ultimately, there is no way to know. It is part of the group culture, IMO and as such subject to multiple (mis)interpretations. Commented Jul 17, 2012 at 1:18
  • Same here. There is one group in my faculty, which follows the alphabetical rule. All the other groups (mine included) follow the order of contribution-but-boss-last rule.
    – user7112
    Commented Nov 3, 2013 at 21:09

Earth Sciences (Physical Geography, Geology etc.). Authors are listed according to their intellectual contribution to a paper. The first author named on the paper is thus the person who has contributed intelectually the most to the paper. The second, third etc, names have decreasing importance (contribution). If more than one person can be considered first author, those names are listed alphabetically and a note to the fact is made in the acknowledgement.

Only persons who have contributed intellectually to the paper are included. Lab assistants, techncians etc, are thus not included (although it still happens).

If a leading scientist, project leader etc. is not first author the lead role may be indicated by refering to that person as "Corresponding Author". This is common when first authors are junior contributors (students).


In physics, with a few notable exceptions (theoretical and experimental particle physics), being first author (or towards the front of the list) indicates having done more work, and being last author (or towards the end of the list) indicates seniority and direction. Both first and last authorships are desirable, as the latter indicates leadership. Typically students will want to accumulate first author papers, while physicists more advanced in their career (e.g. postdocs looking for a faculty position) will want to have last author papers.

Note that in (much of) physics, the last author is one who conceived the original idea and contributed intellectually to the direction of the project. This may differ from some other fields, where the last author is by default the PI or most senior author, or where last authorship indicates contributing funding or administrative direction. Sometimes one sees physics papers where the PI appears as a middle author, and a junior researcher appears last; this usually indicates that the PI was sufficiently involved to be on the paper, but the junior researcher conceived and directed the project.

  • Theoretical high-energy/particle physics and mathematical physics Alphabetic order, probably inherited from mathematics. However, it seems that the rule is not as ironclad as in other fields that use alphabetic ordering (e.g. math, theoretical CS), due to influence from other areas of physics. In particular, papers on the interface of high-energy theory and other areas of theoretical physics (e.g. condensed matter or quantum information), or high-energy theory papers that include authors who are specialists in other areas of theoretical physics, will often use non-alphabetical ordering.
  • All other theoretical physics (e.g. condensed matter, AMO) The first author is usually a junior researcher who did most of the work e.g. the calculations/simulations, while the last author typically came up with the original ideas and directed the project. Sometimes there will be more than one "first author" and this will be clearly indicated on the paper. The role of middle authors vary tremendously: they may be other junior authors who contributed significantly, but less than the first author, or maybe they performed a specific calculation or wrote a particular section or appendix. They may also be senior researchers serving in an advisory role.
  • In the sensor physics sub-field, the order of the authors are typically listed in a similar manner to Earth Sciences, (as described earlier by Peter Jansson). The first author is often the corresponding author. The first author is usually the scientist who not only initiated the project, but also performed much of the experimental practice and analysis. Then, the order is based on the intellectual contributions made - usually of the same research or collaborative group. Other people involved, such as technicians, lab assistants are mentioned prominently in the Acknowledgements.
  • In experimental particle physics, all results are published "by the collaboration", and the entire collaboration is usually published in alphabetical or otherwise arbitrary order. For some collaborations, the author list can have thousands of names, most of which have not read the paper (and may even be unaware of its existence). Further, there is a lengthy internal review process for all published papers. Thus, letters of recommendation are crucial to determine quality of research. Some (generally smaller) collaborations follow a somewhat different (and more informative) practice, however. The scientists who actually worked on the paper are listed first, generally in order of their contributions, with the remainder of the collaboration being listed after.
  • In Atomic, Molecular and Optical (AMO) physics, the trend is that the grant holder/advisor will put their name last, and the grad student who did the bulk of the work will be first author, and other contributors go in between. For notable groups, when you see Author X's name last, you know this is stuff they've been working on for decades, that it's their idea, etc. Putting the students name first is a small gesture of recognition for their hard work and a way to help them start to establish their own reputation.
  • In the absence of a power/reputation differential among authors (e.g two colleagues instead of an advisor and their student) I'd expect the first author to be the one who actually wrote the bulk of the paper and/or the one who did the bulk of the work being reported.
    – argentum2f
    Commented Apr 26, 2022 at 16:21

In the computer science/software engineering and human-computer interaction, the first author is generally the person who both had the "main idea" and led the effort to ensure that the efforts to carry out the research and write the paper occurred properly. The authors are generally then decreasing in order of their contribution. There is generally no consistent policy of putting the PI last in SE or HCI.

Thus, the policy is very similar to the Applied Mathematics answer posted above and quite different from the theoretical Computer Science areas.

  • But what does "order of contribution" mean? How do you judge whether one coauthor contributed more or less than another? And who comes first if Person X had the main idea, Person Y led the research effort, and Person Z wrote the paper?
    – JeffE
    Commented Mar 13, 2013 at 15:29
  • 1
    In my experiences, the authors would agree upon themselves what the author order should be if the division of labor ended up being that diverse. However, in disciplines where author order matters, the question of who should be first author can be hotly debated (and is likely a good topic for a StackExchange question).
    – Irwin
    Commented Mar 13, 2013 at 18:11
  • I merged this answer into the answer about Computer Science that was listed higher up. (FYI, I disagree with the statement that in software engineering there is no pattern to put the faculty last; anecdotally, that's not consistent with what I've observed.)
    – D.W.
    Commented Mar 13, 2013 at 21:04
  • 1
    who should be first author can be hotly debated (and is likely a good topic for a StackExchange question) — I agree! But isn't that this StackExchange question?
    – JeffE
    Commented Mar 14, 2013 at 4:35
  • I interpreted this question as "What does first author mean" as an end goal, rather than "How do we determine who the first author should be?" which I see as a process.
    – Irwin
    Commented Mar 14, 2013 at 17:41

Astronomy: Generally alphabetical author lists are reserved for collaboration papers. The largest ones may even have the first author as the collaboration's name (See for instance this LIGO paper or this arxiv version though the journal version ended up with Abbott et al just to confuse things).

For papers with smaller author lists, the order would be expected to be in order of contribution.

  • The First author will have done most of the work, written most the paper, and built the idea to start with. They are also usually the corresponding author.

  • Middle authors will usually be in order of contribution (sometimes its alphabetical depending on the size of the author list).

  • Last author Does not convey any explicit meaning.


Psychology: There are two distinct traditions to determining author-order in psychology, which we might label the APA and the biomedical traditions. The APA tradition orders authors by level of contribution. The biomedical approach places special importance on the last author, who is often the supervisor of the work. Finally, given the clash of these two traditions, a hybrid model is also emerging where first authors are most important, second and last authors are equal-next-most important, and then third through second last are in descending contribution.

  • The first author is usually the person that led the project, analyzed the data, and led drafting of the manuscript. They may or may not have collected the data personally.
  • The second author: The meaning depends on the author-order tradition applied. Under the APA tradition, they would typically be the second-most important contributor, and where the project is a student or post doc paper, they are often the supervisor. Alternatively, in the biomedical tradition, their contribution is typically not considered to be as important as the last author.
  • Other middle authors are usually involved in one part or another, lending statistical expertise, or subject-matter knowledge. They may also be junior people that collected the data (e.g. interviews, operating technology like EEG nets, etc.).
  • The role of last author(s) depends on the author order tradition implied. They may be the least important contributor. Or they may be the supervisor or PI whose lab collected the data, obtained funding, etc. Data collection in psychology can be expensive and difficult, and take a long time. There can be multiple.
  • Corresponding author is determined by various rules and is given minimal significance with regards to contribution. Corresponding author is most commonly the first author. If it a student-led work, it is also common for it to be the supervisor. Finally, it might simply be someone with a permanent position who might be able to answer questions years later after the first author has moved on.
  • Shared first authorship is rare, but it is becoming more common. Alternating first authorship in close collaborations also does occur.

How do you determine whether last or second authorship implies a greater contribution in a psychology manuscript?

In general, there are a number of indicators that may suggest which author ordering principle was applied on a given paper. Last authors are more commonly important (a) in fields aligned with medicine, neuroscience, and health, and (b) in papers with many authors (e.g., 6+). Second authors are more commonly important (a) in more prototypical psychology subdisciplines like social psychology, personality, experimental psychology, and industrial-organisational psychology, and (b) in papers with fewer authors. In general, this seems to reflect patterns of collaboration. For instance, if academics are collaborating with the biomedical field, they absorb that tradition.

More generally, second and last authorship tend to be more important roles where the first author is a student or post-doc. In those cases, it is often the case that either the second or last author supervised the work.

Given the ambiguity in psychology about the relative importance of second and last authorship, some academics in psychology will highlight the number of times they have been a lead author, which is often specified as first, second, or last authorship.

APA Style Manual 7th Edition The Style Manual has the following to say in Section 1.22 With regards to professional authors (e.g., where it is not the work of a doctoral student):

Principal authorship and the order of authorship credit should accurately reflect the relative contribution of persons involved... The general rule is that ... principal contributor appears first, with subsequent names appearing in order of decreasing contribution. In some cases, another principal contributor appears last. These conventions can vary from field to field and from journal to journal... If authors played equal roles in the research and publication of their study, they may wish to note this in the author note.


Art history: The humanities are still heavily invested in solo authorship. The first author is generally considered to be the one who researched and wrote the vast majority of the paper.

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