I am leading a research project which involves a number of international collaborators. We have been working with one collaborator since early this year to develop a Spanish version of the survey we are launching through his University. We are ready to launch the survey, but he is constantly missing deadlines, taking weeks to do small tasks, and being very vague when I ask where the hold up is.
He is important and has been valuable to this project. He has an extensive network that will see the survey and significantly boost the research capacity. However, he is simply offered co-authorship on the papers so no financial incentives are present - it is essentially voluntary.
I think the problem is stemming for his continuous need for 'refinement' and perfectionism. I have started setting launch deadlines, asking where the issue is, and that we need to put more energy into the launch. However, he got back saying we need to continue refining the survey, and that the project will be launched this week - which he has said multiple times - always delayed.
We obviously need to air the issues surrounding this lack of action. I am beginning to see this relationship as a waste of time, however.
How do i communicate with him effectively, striking a balance between strictness and understanding? How would you manage this individual?