My «fairest» interpretation of the current albeit controversial research
surrounding this particular issue is that
bias does not exist across teacher - level estimates, but it certainly occurs when teachers are non-randomly assigned highly homogenous sets of students who are gifted, who are English Language Learners (ELLs), who are enrolled in special education programs, who disproportionately represent
racial minority groups, who disproportionately come from lower socioeconomic backgrounds, and who have been retained in grade prior.