When I was recently serving on an interdisciplinary committee that had to read dozens of CV's, the inevitable topic of authorship order conventions arose. In order to fairly evaluate these CV's from across the entire spectrum of Academe, we had to know what the convention was in each field.
Even when told that the convention in, say, economics is for alphabetical ordering, it is difficult for faculty who are not in alphabetically-ordered fields to overcome a bias against someone whose name is always in the middle of a pack of authors. I have read with great interest about studies that show that even within fields in which alphabetical ordering of authors in the norm, there may be a subconscious bias against authors with surnames late in the alphabet, and therefore negative consequences for hiring, promotion, tenure, and awards.
On my committee, as we evaluated one CV from a professor in a field with alphabetical ordering of authors, a committee member was very frustrated because the article citations listed the CV person's name first, followed by 'with A. Person and B. Person'. This committee member wanted to see the citations written out in the correct order. I said "But we know the correct order because the order is alphabetical." Even so, my colleague insisted that seeing the authorship written out in the correct order was essential. He felt that the CV person was somehow being slightly dishonest by making his name the most prominent in each citation. Well, given that the CV person's last name began with R, I didn't blame him. If he wrote out the citations completely, he would have been last or near-to-last in them all, and this was not a field that valued last authors. It seemed like a lose-lose situation to me.
Regarding fields in which being last author is customary and prestigious, indicating the research group leader: I also saw on my committee that people in fields in which last author implies the least contribution to a paper have trouble overcoming a bias about the (in)significance of last authorship.
In one of the 57 ethics training courses we have to endure at my university, I was told that even if I provide the funds for a particular research project that is conducted in my lab, unless I contribute something else to the study (e.g. ideas, data, writing), I cannot (= should not) be a co-author, not even as a caboose author. Conflicted feelings and ethical issues related to last authorship led to discussion in my committee of whether someone whose CV had his name listed last on every single publication had really done any of the work. I think it was obvious that he had, based on other information we were evaluating, but again, people in fields in which last authorship = the least contribution had trouble overcoming a negative reaction to last authors.
I have participated in both alphabetically ordered and non-ordered authorship cultures and think that there are problems with both schemes. Alphabetical ordering seems simple enough, but if anyone with a surname after D is going to be disadvantaged in their career, then that system is not as objective as it might seem.
Ordering by relative level of contribution has its own complications because in some cases you have to decide the order of authors who contributed at similar levels to the paper. And who should be first author if one author supplied the ideas and one supplied the data?
In some cases, the addition of a third author to a paper means a major decrease in exposure (and therefore name recognition and therefore possibly career advancement) for the second author, who is relegated to being part of the 'et al.' rather than having their name listed more prominently in journals that have such citation formats within the text.
Maybe we should publish more single-author scholarly articles? No, that's not good either because that makes us look like we don't work well with others, and are not multi-, inter-, or even transdisciplinary. Single and few-author papers were, however, important to me earlier in my career because I wanted there to be no doubt that I had played a major role in these publications. I think this is particularly important for early-career women scientists.
These days, I don't care where my name falls in a multi-author paper for which I was a mid-level contributor, though sometimes having my name buried in the et al. of a paper can lead to strange situations. Several times in the past year, I have had people talk to me about a particular paper on which I was a co-author, and I initially assumed that my role was known because my name is on the paper, albeit somewhere in the middle of the author list (which is not long). The repeated use of "they", as in "they said this" and "they concluded that" is a clue that this assumption is flawed. I like to say "Yes, and their paper is so well written, and I particularly love Figure 4" etc. I don't actually mind it if someone doesn't instantly recognize my authorness -- I certainly don't have the author lists memorized for all the papers I read -- but it would not be so entertaining if being recognized for my contribution mattered to my career more than it does at this stage.
9 months ago