Everything in the world follows some rules - the items move according to classical mechanics, and optimise some trajectory according to some cost function. Apples follow the gravity and fall down from the trees straight towards the ground, and the electric current flows from high towards low electric potential according to the shortest possible trajectory. People also construct their own cost functions, and adjust their behaviour according to the rules present in their environment.
I am talking about this simple fact as I have spent excessive amounts of time thinking about the mechanisms that drive people against each other in science. PIs are simply not enough motivated to make their students happy, as they have not enough incentives to spend their time and energy on even thinking about this topic. What pays off in academia the most for your survival, is to maximise the amount of papers and grants that you get, without thinking about the associated human factor - mostly because you simply cannot put your success as a supervisor or a mentor, into your CV. Namely, since the success in any of the above is not a criterion that could influence your future funding opportunities, or future positions you take, it is prioritised so low that almost no one ever actually finds time for this in practice. I believe that people are good by nature, but they also have a natural survival instinct, and they will always prioritise actions that facilitate their survival - and there is no point in blaming them for this. If you wish people to orient themselves towards a new quality, anything other than publications and grants, you need to change the rules so that taking action in this direction will help these people in achieving their highest priority - which is, again, a survival. Furthermore, I believe that positive, ‘American-style’ motivation works just best. Silence is enough of a punishment, and being overlooked is painful enough to motivate people to make their best, especially if they are naturally ambitious.
Therefore, let us make a mind experiment. What would happen if every university announces a yearly ranking of, say, ten best supervisors, according to the students’ and PhD students’ anonymous evaluations? What would happen then? To my mind, this little rule would launch the whole avalanche of good events.
So, what would happen first would be a brand new possibility for someone who has always been a good supervisor, to put this statement officially as a badge of honour in their CV, and indicate this achievement by grant writing and applications for positions. This move would motivate good supervisors to be even better at what they are doing, as they would have a sense of acknowledgement for their, otherwise ignored, efforts.
Secondly, I genuinely believe that grant writing agencies have an interest in giving money to the right people. This often means ‘people who publish the most’ but this is not the only criterion. I bet that many of the board members in the major grant writing agencies would happily credit grants to people who might be publishing a little bit less than others but at the same time, they have an ability to create a good, healthy atmosphere at the work place, and mentor other people well. Especially given that many of the granting agency representatives ARE former frustrated and depressed PhD students who were bullied by their supervisors. The issue is: granting agencies have no idea how to tell who is a good mentor, and who is not. Most of the time, they do not know the applicants personally. If there were official white lists released by universities, it would be much easier for the granting agencies to take quality of mentorship into account. I believe in good intentions of the granting agencies, and that they would make a good use of the information on who the applicants actually are, and how well they treat other people, especially students.
Thirdly, how do you choose a job as a good software developer? Would you rather choose for Google, or for a small startup? Well, most people compare the salaries, and take them into account while choosing the job. If they feel competent and competitive enough, they will attempt to get a job in a company that offers the best money. In many countries like in the Netherlands, all the salaries in science are standardised, therefore, most students would like to choose a job in which they can develop the most. But how to choose a good supervisor, especially if you come from abroad, and you simply do not know this particular environment? I know a lot of good students who come from other countries and then regret their choice of a supervisor, mostly because they have no prior information about the quality of a supervision, and so they made a random choice.
Next to that, if the white lists are revealed, good supervisors would get more good applicants coming from overseas, which would be yet one more benefit from becoming officially listed as a good mentor. This would also motivate other, worse supervisors to improve - regardless of whether they have a natural motivation to be good to students, or rather, if this is just a self-oriented action calculated to get better students and produce more papers. I think that you cannot really change people’s personality but you can still influence their choices - and only the outcome matters.
Lastly, creating such a list costs the university absolutely nothing. Honestly speaking, I did not find one downside of such a white list so far; to my mind, everyone would only gain on this. So, any institution willing to set up such a new hall of fame? :)