As an early-career faculty member and advisor, I feel I could learn much from my PhD students' feedback about my mentorship style, how I could better support their learning and career development, the lab dynamics that I have fostered, etc.
I am interested in what the best way would be to invite constructive feedback from students (as well as other lab staff members) on these topics. I am well aware from teaching that students can be reluctant to provide feedback in face-to-face conversations. For this reason, I lean toward emailing individual students saying that I would welcome feedback on these topics, and they can feel free to provide it by responding to the email, or by letting me know they'd like to discuss in person. I suppose another option is an "anonymous" Google Form with a feedback box, although with a small research group, it really wouldn't be very anonymous in practice. Last, I could have an open feedback session at a lab meeting: this provides strength in numbers and a chance for discussion with other lab members, but obviously no privacy.
What practices have others used successfully or unsuccessfully?