Studies of teacher rating form (TRF) generalizability have focused primarily on two classes of variables: student characteristics and teacher characteristics. Since the goal of most TRF researchers is to show that TRF scores correlate with teacher-produced student achievement, a suitable generalizability study would investigate the relationship between student or teacher characteristics and the correlation between TRF scores and achievement scores. A TRF can only be considered generalizable if the validity coefficient is unaffected by student or teacher characteristics. Since researchers have not studied the generalizability of the TRF validity coefficient, the generalizability of TRFs is still an open question. (Author)