Does the professor spend time with his student beyond the 1-hour weekly/biweekly meetings? Is he/she aware/supportive of the big events that happen in his lab members’ lives, such as having a broken leg, engagement, pregnancy, etc? Contact the current and former lab members and ask questions about this.
Look at the list of alumni on the professor’s webpage: Does he/she make an effort to know where the former lab members are now? Or simply the names are listed there? That helps to understand how well the PI cares about the former lab members, they are his/her resume after all.
Does the professor encourage trainees to take time away from their research to do other activities that will enhance their training?
This includes attending conferences in-person paid by the professor, or special summer courses suggested by the professor.
Sometimes trainees will need some time away from the lab for parental leave, is the professor supportive of that? If you are not planning on having kids, just inquire about this to learn how he/she treat the lab members. A good mentor will be supportive of this for male as well as female trainees
How does vacation time is treated? Is it ok to take two-three weeks off every year to go back home and see the family?
Does that lab have only postdocs? Ask why? Labs with nearly all postdocs may suggest that the lab head does not enjoy, time spent mentoring
Talk to the last 3 graduate students or postdocs who left the lab. It is critical that you determine the faculty member’s track record of mentoring success. When you talk to people especially ask them about the issues they have faced with the PI, and how they solved them. If you do not like what you hear, you better continue the search.
As you gauge the mentoring environment of a prospective lab, make sure to ask whether the students are generally happy. If not, this is a warning sign. Are the students excited when they talk to you? DO they have a lot of good things to say about the PI? Read between the lines
Does the PI care about his/her own career more than his trainees? Here are some signs that a prospective advisor is thinking more about his own career and less about your career:
He/she never mentions his students’ names when he presents their work in a talk or only mentions them in a long list in small print at the end of the talk. Watch PI’s talk online, surely you can find some.
He/she does not practice the students’ talks with them,
He/she tells you what experiments you must do, and does not engage their opinion on the decision making.
He/she allows the students’ papers to sit on his desk,
He/she refuses to allow students to take their projects or reagents with them (or fails to make sure they have lots of good starting points for projects in their own labs).
Are people scared/stressed to tell the PI something went wrong? Ask former lab members how these conversations are being handled
Graduate students and postdocs are paid little. Does the PI make any effort to help them such as increasing the pay above the minimum level? In certain places such as Stanford University, even the postdoc pay is below the poverty line, let alone the graduate student pay. Ask former lab members and see how the PI helped when there was a financial emergency in their lives?
What happens after people leave the lab? Can they reach out to the PI and collaborate or ask for help? Some PI makes their former lab members disappear and block their access immediately, advises the lab members not to talk to the person who left, and even sends angry emails.