Based on my interest in authorship practices in ecology, I decided to look at papers published in Ecology in each of the past seven decades to see how corresponding authorship changed over that time.* I looked at the first (or second**) issue of Ecology in 1956 and every ten years thereafter.
tl:dr version of the results: Not surprisingly, the number of authors increased over time. For corresponding authorship, I found that, in 1996 and earlier, the corresponding author was almost never indicated. Looking every 5 years from 2001-2016, the first author*** was usually the corresponding author, though expanding the analysis to include AmNat and Evolution**** suggests that some of the changes might be due to some of the more mundane aspects of publication.
The purpose of my analysis wasn’t to look at how the number of authors on Ecology papers changed over time, but that was a striking feature while going through the issues. (This is a feature that has been noted regarding the scientific literature generally. I feel sure someone must have made a similar plot specific to ecology papers, but I can’t find it. If you know of one, please let me know in the comments! As I say in footnote 4, I’ve been told Daphne Fairbairn did a similar analysis for Evolution, but can’t find that online.)
The first paper I saw that had a note related to correspondence was Kalisz & Teeri 1986, which includes a footnote that says “Send reprint requests to first author”. This surprised me, since I would have assumed that most people would send the reprint requests to the first author. I’m not sure what the story is behind that footnote. One question this raises (that I would love to hear thoughts on in the comments!) is what the default was in the pre-email days when author addresses were all listed. If you wanted to find out more about a paper, who did you write? The first author? The last author? (Assume you didn’t know any of the authors personally.) I thought it was the first author, but this footnote makes me wonder.
The next paper that had a note related to correspondence was Murcia & Feinsinger 1996, which gets bonus points for having authorship order determined by a coin toss. (I have a post on fun ways of deciding authorship order.) Their footnote says “Address correspondence and reprint requests to second author,” making it the first footnote I saw in this analysis that had what I would consider a standard correspondence footnote.
My scan of old issues indicates that the email address of at least one author started appearing in Ecology in 2001. Looking at 2001, 2006, 2011, and 2016, it’s clear that the first author is usually the corresponding author for Ecology papers. The proportion of papers with the first author was the corresponding author remained high over the whole period. 2016 had the highest proportion of papers with the last author as the corresponding author, but it’s still a pretty low percentage.
The pattern in Ecology made me wonder if it would hold across journals. I initially started to look at AmNat, but quickly ran into a snag where, in 2006, almost all of the authors had their email addresses listed. Based on an email conversation with Trish Morse at AmNat, it sounds like that was a reflection of their submission/peer review system, so I decided not to include AmNat in my analysis.
Instead, I looked at Evolution. Right as I was about to start the analysis of the Evolution data, an evolutionary biology colleague stopped by my office. When I explained what I was doing, her guess was that the proportion of first authors as corresponding authors would increase, which was the opposite of what I was guessing. We were both kind of right (well, she definitely was definitely right, and I may have been, too):
It seems clear that the number of first author corresponding authors is higher now than it was 15 years ago. It’s a bit less clear for last author corresponding authors, but, as for Ecology, 2016 was the year with the highest percentage of last author corresponding authors. The biggest decrease of time was in the percentage of papers where both/all of the authors had their email addresses listed (lumped together into “all” in the figure). And, in some of the earlier issues, there were some unusual combinations (e.g., first and third authors on a paper with four authors having email addresses, but not the other two). For 2016 (with a reminder that this analysis just includes data from the first issue), the corresponding author was always the first or the last author.
One issue this analysis suggests is that some of these changes over time may reflect changes in submission systems and/or people working out what it meant to have an email address on a paper. AmNat and Evolution both show us that it used to be relatively common to have email addresses for all authors, but that this is now rare. So, while I started this analysis thinking that it would tell me about peoples’ big picture views on corresponding authorship, now I’m wondering if some of it just reflects more mundane aspects of the process of submitting a paper.
Then again, maybe that is exactly the point: prior to having just one or two people with an asterisk next to their name indicating that they should receive the correspondence, corresponding authorship wasn’t a thing that people could note or track and, therefore, wasn’t something people really cared about. Now that we have that asterisk, it is becoming something that people care about and argue over.
One of the things I’m most interested in is whether being corresponding and/or last author is a position of prestige, which is harder to get at with this sort of analysis. But my earlier poll results suggests that most ecologists now view the last author as the senior author, and I am not the only person to have noticed and commented on the apparent increase in the number of last authors who are corresponding author.
The biggest motivation for me continuing to do this analysis is thinking about how early career scientists might be influenced by these views and practices. To me, it’s problematic if some people view last and/or corresponding authorship as something prestigious but others do not. Knowing that at least some people view corresponding authorship as something valuable, I will continue to have my default be for my grad students and postdocs to be corresponding author. What to do about last authorship seems a bit trickier for pre-tenure folks with their own labs. At Georgia Tech, I was told directly that I should be last (and corresponding) author on papers coming out of my lab.***** But, when I got to Michigan, it seemed like some of the senior folks I spoke with expected that I would have been first author on most papers out of my lab while I was an assistant professor. That argues for figuring out the local culture, but, even with doing that, that doesn’t solve the problem of tenure letter writers having different views on this, and of the potential knock on effects on grad students and postdocs in the lab. Those issues seem much less tractable to me.
Do you think it’s a relatively recent thing that people view corresponding authorship as something that matters? Do you think that people care about it now simply because we’ve created a way of indicating it (by having one or two people who get an asterisk next to their name)? What’s the best solution to this problem for early career folks? (Before you say we should just go to authorship contribution statements, read this post of Jeremy’s for more on why those are problematic, too.)