There are different guidelines for what qualifies a researcher to be an author on publications. I've just seen a case on Twitter where the PhD student was puzzled that the supervisor was going to publish an article from his/her data collection without including him/her.
For PhD students: do you think this is fair? have you discussed it with your supervisor?
For PhD supervisors: What criteria do you use for establishing the authorship policy in your lab/research group?
I see this a huge gray zone in research, and clarity/transparency would help everybody :)
Thanks!