When Prince George's County Public Schools created a teacher mentor program, administrators also created a system for evaluating it with clear expectations and goals at the outset. Precisely defining objectives enabled leaders to see their progress, determine what needed to change along the way, and build support for the program.

A statewide survey on teacher induction and mentoring programs, conducted in Ohio during 1991-92, asked districts to report on the presence or absence of program components required by the Ohio standard for entry-year certification. Most districts reported having mentoring programs that had major positive effects, though there were some problems.…