Richard Ingersoll of the Graduate School of Education and the School of Arts & Sciences is cited for suggesting that the more comprehensive a mentoring program is the more likely a teacher is prone to stay at a school.
http://www.npr.org/sections/ed/2015/10/22/450575463/it-s-okay-to-cry-in-your-car-fighting-disillusionment-as-a-first-year-teacher National Public Radio