• A teacher's peers include all other teachers in the same school that teach the same grade

• A teacher's performance is affected by the quality of their peers

• "changes in the quality of a teacher’s colleagues are associated with changes in" their, "students’ test score gains"

• A teacher's performance increases when the quality of their peers' increases

•Certified and licensed teachers are more responsive to their peers

• Teachers share resources

• Less experienced teachers can learn from more experienced teachers and are, therefore, more responsive to peers

• Students can be affected by a teacher's past peers