Identifying and Adjusting for Biases in Student Evaluations of Instruction: Implications for Validity

Student evaluations of teaching effectiveness are widely used for improvement of instruction and for administrative decision-making. Several kinds of contaminating variables may influence these ratings. Criteria for identifying such contaminants are set forth. Results of a search for extraneous, biasing variables at the high school level are reported. Of the several potential extraneous influences studied, student motivation/preference and class size meet the criteria. It is concluded that student rating forms should make provisions for adjusting for these and similar unfair influences.