Asking for recommendation letter from manager for graduate school I asked a mentor on my research team to write my letter, but he has not been responsive (he normally is terrible at keeping up with e-mails, this is no different). My manager only saw the high-level aspects of my research, but the mentor isn't responding and asking my manager might prompt my mentor to help him write the letter.

Is this a good way of approaching the situation? If not, what would be a better way?
It seems reasonable to me, especially since rec letters are typically on a hard deadline. Worst-case, line up another recommender in case the one you hope for doesn't come through.

Slightly tangential, but... I've noticed a few things about rec letters from people outside academe that can make them harder to take seriously:


Extremely brief -- like, five sentences or fewer brief. Cover-letter length is more desirable.
Vague and general, not giving a strong impression of the applicant's specific individual potential
Make mention only of very low-level skills and abilities (e.g. showing up to work on time -- nice to know, but not exactly helpful in an admissions decision)


You may want to coach your recommender a bit, carefully and politely, about things it would be useful for them to say. You don't have to ghostwrite (and probably shouldn't; that's on the razor edge of ethics), but you can ethically suggest anecdotes about your work, or projects you've done, that you think say something unique, positive, and discipline-relevant about you.