Question: Let's say you had a doctoral student who you were main supervisor for {~advisor) throughout their data collection and most of their write-up, but just before they finished they changed to another main supervisor and you became deputy supervisor (you moved to a new institution in another country and they wanted someone close at hand). Let's say you then counted this student on your CV as supervised to completion as main supervisor because this is 90% true and because these CV points are important for things like promotion. The plan if anyone ever called you out on this would be to just explain the situation as it is and say that 90% of the work felt like it justified the claim. The student is in Sweden (where the regulations say students have the right to supervisor change without even having to make a case) and the supervisor is a Lecturer (~associate prof) at a UK university who wants to make Reader (~full prof) some day. Is this a bad idea? What is likely to go wrong?

Answer: 
On a generic CV, I would simply make a section of "Graduate students supervised and co-supervised", and include this student. In this context it wouldn't be necessary to go into detail about whether the supervision was "to completion".

But for something like a promotion dossier, where you're asked to tick boxes, I would go to whoever is responsible for overseeing the evaluation process (department head, promotion committee chair, etc), explain the situation, and ask what you should do. If at all possible, get an answer in writing. Then, when you fill out the form, attach a note saying something like:

> 
> One student was supervised by me for about 90% of their thesis work (stages X, Y, Z), and then changed supervisors for the last 10%; I am officially listed as their deputy supervisor. I spoke with Department Head Smith on October 24, 2018, and she advised that it was appropriate to include this student as "supervised to completion".
> 
> 
> 

If Smith says "no, don't count it", then you attach a similar note saying "Smith said not to include this student, but I believe that this is a similar accomplishment to supervising a student to completion".

Since academic achievement is generally self-reported and "honor system", this means that any attempt to "cheat" is seen as a serious ethical offense. If someone on the evaluation committee is hostile to you, they could use something like this as ammunition to wreck your entire promotion case. ("Candidate says supervised to completion, but student's dissertation shows someone else as supervisor. Clear-cut fraud.") So that's what could go wrong. But if you disclose the situation, and get someone else to pre-approve the way you're filling the form, you eliminate the possibility; maybe it won't be counted in your favor, but at least you can't be accused of fraud.
### tl;dr: Just check the binding regulations.

You're asking the wrong people. Some of us think it's bad, some of us don't. In some universities the criteria are this way, in some - that way.

So just open the administrative/academic/promotion-related regulations for your university or department, and see what it says: What *exactly* is supposed to count for promotions? If the wording is not entirely clear, consult the head of your department.

Now, you might be wondering "Ah, but what if he tells me to change my CV, while in fact the promotion committee would have never looked into it?"

Well, maybe. But:

1. It's unethical to do so.
2. The expectation of benefit/damage over both cases is not high enough for this to be appealing even if you have no ethical scruples (or if you think the promotion process is otherwise unfair).

having said all of the above I must also tell you that: **Look, you didn't supervise that PhD to completion.** What can I say? You just didn't. You had planned to do it; you would have done it, had the circumstances allowed it; you put in most of the effort towards it - sure. But at the end of the day, that's not what happened.