This study tested two theoretical models of perceived understanding as a potential mediator of perceived teacher confirmation and students' ratings of instruction. Participants included 651 undergraduate students who completed survey measures. Results of structural equation modeling provided greater support for the confirmation process model, whereby students' perceived understanding partially mediated the effects of perceived teacher confirmation on both teacher credibility and evaluations. Further, perceived teacher confirmation accounted for 64% of the variance in perceived understanding, and both confirmation and understanding accounted for 70% and 72% of the variances in teacher evaluations and credibility, respectively. Among the more important implications of this research is the finding that confirming behaviors have both direct and indirect effects on students' ratings of instruction. (Contains 2 tables, 4 figures, and 1 note.)