As I learned when I was a PhD student mapping collaborative research networks around sustainability based on author lists on papers, the presence and order of names can mean many things. It depends partially on the type of paper, such as whether it is led by a student, and the discipline from which it originates. When you work in an interdisciplinary domain, things get fuzzy. When I lead papers with colleagues I try and order simply by contribution, and I think they do too. But it has become clear to me that student paper practices differ.
I was mentored in a setting where the ‘lab’ head or PI went last on papers by students in that lab, and I have continued that practice. When ‘my’ students publish, i.e. I am the supervisor or co-supervisor, funding the work to greater or lesser degrees, I put myself last and insert other names between the student’s and mine in general order of contribution. But I have noticed that other (generally social science) colleagues put me last when I am only a committee member on papers by ‘their’ students. These two practices present different impressions, but I only have control over one. I will continue putting myself last on papers led by students I supervise, to maintain consistency with past work and because it feels like a needed acknowledgement of the time and insight that colleagues contribute to my research programme.