Advice on Ph.D. applicants moving from different univ after several years

[born_a_prof]

I have a received a few such applications recently, and I am wondering what to make of them. One student is applying to move to my group after spending 4 years in a different Ph.D. program (at a significantly higher ranker university than mine) and passed the quals. I am intrigued since she has a strong CV, and it could be a case of bad fit. What would be some questions you would ask such an applicant in an interview ? Red flags ? Would you require a letter from the current supervisor ?
I see only one publication, but several preprints...so it is not that she is totally unproductive.

[nonsensical]

This might seem obvious, but I would ask why they want to work with me and why they want to leave their current place. I'd also talk with their current supervisor and perhaps others in their program (other people they've worked with? people they've TAed for or from whom they've taken classes?). My sense is that these conversations would be more informative than a letter.

[Puget]

There could be reasonable explanations (e.g., advisor didn't get tenure/moved/died and no one else there does similar work, or they have to move due to family situation and can't finish remotely), but it seems very odd if the applicant doesn't give one and raises a lot of red flags. I'd definitely want to talk to a colleague at the student's former program, not just rely on letters-- People are likely to be more open on the phone than in writing.

[Durchlässigkeitsbeiwert]

I would suggest not to contact student's current supervisor without said student's consent.
As in normal job search, contacting prospective employee's current employer is a very bad practice.

[Ruralguy]

Can't get anywhere without asking the prospective student, so do so.

[fizzycist]

I would suggest not to contact student's current supervisor without said student's consent.
As in normal job search, contacting prospective employee's current employer is a very bad practice.

+1

I'm not sure how grad applications work at your place (they apply directly to a faculty advisor or departmental committee handles all applications?). But either way, if you are serious about accepting an advanced student into your lab, I'd start with a video conference and discuss research and then ask for a candid discussion on why they want to leave. Usually the answer comes out at that point and you can decide whether it is a red flag for you or not. If I can't coax any type of straight answer that is its own red flag and I'm done.

In my experience the advanced student transfer means either: 1. Something bad happened with advisor and it is advisor's fault, 2. Something is off with the student and they have been unable to find/keep an advisor. 3. They got kicked out for failing some sort of qualifying exams,

Not saying there aren't other reasons but I haven't seen them. I've seen students with situation 1 do quite well in our program. Students in situation 2 never made it in. One student in situation 3 did make it in and results seem a bit mixed.

[Puget]

I was not suggesting contacting the advisor if they aren't one of the letter writers, but if someone is listed as a reference and wrote a letter, I think it is assumed by all parties that it is legitimate to contact them for more information. I would not accept such a student without speaking frankly to at least one of their references rather than just trying to read between the lines of a letter.

[AJ_Katz]

+1 to what others have already said.  In my experience having graduated multiple PhD students that transferred to my group from other labs, I generally find that these students are not inherently poor performers...  they simply have a bad fit with their advisor that results in poor performance.  Expect these students take more work, but it's not because of lower aptitude / performance, it's because there's a lot less time to get them up to speed and onto the path to graduation on a shortened timeline.  But these students can be some of the best!  They've struggled and they are focused on finding a path to graduation, so they are both super appreciative and ready to put their nose to the grindstone to get the work done.  If it was me, I would set up a Zoom call to talk with this person, get to know why they're interested in working with me, and find out what their expectations are for the project and graduation timeline and career goals. 

BUT -- beware the student that doesn't want to do research in your area of expertise.  If their expectations for the dissertation are unreasonable ("I'd like you to be my advisor but I don't want to do a project in your lab because I just want to finish the project I started with my old prof x"), then I would kindly give them advice to try to stick it out with their current advisor.  It will hurt your productivity and/or provide limited benefit to you if the student does not want to do a project related to your existing program.