Structural equation modeling is used to examine the nomological relationships between the five latent constructs that comprise the Student Instructional Rating System (SIRS), a widely used student evaluation of instructor form. Our results indicate that input factors, that is, course organization and student-instructor interaction, influence the endogenous factors, that is, instructor involvement and student interest, in a positive manner. However, the factor—course demands affects these endogenous factors in a negative manner. In addition, course demands is also negatively associated with the other two input factors. Despite their apparent intuitive appeal, users of student evaluation forms often ignore these relationships. The authors hope that users of student evaluation forms take these relationships between the latent constructs into account when using the results.