Suppose that my team received funding for a project to "deliver X in time Y". It is implied that each researcher will contribute, more or less, equally.
When is it appropriate to make this explicit? In other words, in this scenario, what is a commonly accepted threshold to confront an author about their lack of participation (when their contribution is half of what is implicitly expected, a tenth, etc.)?
I've never liked the idea of implicit distribution of work. In my projects, I always try to break down the project into smaller parts and parcel them out at the onset of the project. Regular meetings/emails make sure everyone stays on track, and I also use a project management software: Asana to keep track of how things are going.
Better to be upfront about things so that everyone is clear on their role instead of being in a situation where we have to worry about having an uncomfortable confrontation!
People's contribution to projects is mainly determined by two factors:
When somebody is not contributing, they are lacking in either category (or in both). So the first thing you might do, is to inquire in a polite and sensible way where the problem is. Is the co-author lacking ability (time, tools, ...) or motivation? When you know the answer, you can figure out together how this can be resolved.
When you approach this as described above, you can do this immediately. You do not need to wait until some threshold of (un)acceptable behavior has been violated.
A blunt confrontation rarely delivers anything productive, certainly not in the long run.
