What factors influence views on last authorship in ecology?

As summarized in my post giving the major results of our authorship survey, there seems to have been a rapid shift in views on last authorship in ecology. When I started grad school, the predominant view was that the last author was the person who had done the least work. (Indeed, I am last author on a paper from when I was a grad student because I did the least work on the project.) But the survey found that 43% answered a solid “Yes” to the question “For ecology papers, do you consider the last author to be the senior author?” An additional 43% answered either “It depends, but probably yes” or “Not sure, but probably yes”. Thus, 86% of respondents view the last author as the senior author.

As far as I know, we don’t have great data across time regarding views on this. The best comparison I know of is to a smaller survey done in 2010 by Ethan White. (I based the first draft of my survey on Ethan’s.) In that, only 19% of respondents answered “Yes” to the same question, with an additional 33% answering “Not sure, but probably yes”. (That earlier survey didn’t have the “It depends, but probably yes” option. That was added in based on feedback on the initial survey I drafted.) So, while it would be nice to have more data on this, it seems that views on last authorship in ecology have probably shifted pretty rapidly.

The goal of this post is to explore whether there are factors that are associated with views on last authorship.

Prior to analyzing the data, my expectations were that people:

1. with more recent PhDs;
2. who do primarily molecular research; and
3. in Biology departments (rather than EEB or Nat Res departments)

would be more likely to view the last author as the senior author. I also wondered if geographic location and the amount of interdisciplinary work would influence views, but didn’t have specific hypotheses. I haven’t done any formal hypothesis testing (even though it’s okay to use statistics for exploratory analyses!) I decided before doing analyses that, in cases where I was comparing two groups (e.g., basic vs. applied), the difference would need to be about 10% before it seemed noteworthy. That number is somewhat arbitrary, but I wanted to have something in mind at the start.

Results

Were people who got their PhD more recently more likely to view the last author as senior author? The trend isn’t overwhelming (Figure 1A). Current students and recent PhDs had the highest percentages for the “yes” options, but the only major difference seems to be that people who do not have a PhD and who aren’t a current student had different views (but with the caveat that this group represented only 2% of responses). If I binned the data into 0-10 years since PhD and 11+ years since PhD, I’d probably get a difference, with the latter being less likely to view the last author as senior author. But the 11-15 years since PhD group is most extreme, so I’m hesitant to do that comparison.

Figure 1. Results of question on whether the last author is the senior author, broken down into different groups: A) years since PhD, B) primary research area, C) department type, and D) basic vs. applied research.

Did research area influence views? The pattern that seems most striking to me in the data related to research area is that the two evolutionary biology groupings (“Organismal Evol” and “Mol Evol” in Figure 1B) were the most likely to give one of the “yes” responses. My thought that the molecular folks might be more likely than organismal folks to view the last author as senior author held for ecologists but not for evolutionary biologists (Figure 1B); however, it’s worth noting that the most straight “yes” answers were from people doing molecular evolution.

I was completely wrong in thinking that folks in ecology and evolutionary biology (EEB) departments would have different views than those in Biology departments (Figure 1C). Instead the difference was between EEB/Bio folks and those in Natural Resources departments. Overall, people in Natural Resources departments were much less likely to view the last author as the corresponding author. This probably helps explain the difference between those doing basic and applied research (Figure 1D), but that difference didn’t reach my 10% threshold.

There also seems to be interesting geographic variation (Figure 2A). Focusing just on North America vs. Europe (because those are the only two where we had substantial numbers of respondents; see Table 3 in my earlier post), Europeans were more likely to view the last author as the senior author.

But the most interesting pattern to me overall is that there is a clear relationship between the frequency of doing interdisciplinary research and views on authorship, with those doing the most interdisciplinary research being the least likely to say the last author is the senior author (Figure 2B). This surprises me! If I’d been forced to guess ahead of time, I would have predicted the opposite pattern. (It actually surprised me so much that I pulled up the data in Excel and manually sorted things to make sure I hadn’t messed up the code somewhere. My manual sorting and binning matched the above.) I would love to hear thoughts about this! It seems counter to the idea that ecology traditionally has had less of a view that the last author is the senior author. My best guess is that that is a view based on ecology vs. medicine (or molecular and cell biology), and that the interdisciplinarity result is driven by people doing interdisciplinary work with other disciplines (e.g., geology, engineering). I don’t know what the traditional views on last authorship are in those fields.

Those are all the analyses I had planned related to the first question. If you think I missed something interesting (for which we have poll data!), let me know. And I’d love to hear thoughts in the comments. I’ll continue to post results as I get them written up.

Acknowledgments: The same ones from my earlier post apply, but I especially want to note that the figures in this post only exist because of help from Rayna Harris.