Many personnel committees at colleges and universities in the USA use student evaluation of faculty instruction to make decisions regarding tenure, promotion, merit pay or faculty professional development. This study examines the construct validity and internal consistency reliability of the student evaluation of instruction (SEI) used at a large mid-western university in the USA for both administrative and instructional purposes. The sample consisted of 73,500 completed SEIs for undergraduate students who self-reported as freshman, sophomore, junior or senior. Confirmatory factor analysis via structural equation modelling was used to explore the construct validity of the SEI instrument. The internal consistency of students' ratings was reported to provide reliability evidence. The results of this study showed that the model fits the data for the sample. The significance of this study as well as areas for further research are discussed. (Contains 1 table and 1 figure.)