The effects of student personality type on ratings of instructors are examined. Research studies are reviewed and categorized into three groups: field independent/dependent cognitive style of subject; general personality style as measured by the Myers-Briggs Type Indicator; and perceived needs states of students. A new measure, the Johnson Decision Making Inventory, is introduced. For the present research, two different samples of college students were used. The first was a group of students enrolled in an introductory chemistry course, and the second was a group enrolled in a general studies art appreciation course. All students filled out the Decision Making Inventory and Frey Instructor Rating instruments. The analysis of variance for the two classes yielded very different results. Both professors were of the same decision-making style, yet their evaluations were unalike. Overall, the art professor was evaluated much higher than the chemistry professor. Numerous explanations for the differing results are offered. It is suggested that confidence in the findings would come with a tighter control on instructional quality and student self-selection and increased reliability of the instruments used. Charts are appended. (Author/GSK)