Students tend to give low ratings to instructors who teach demanding courses, such as math, engineering and science, while granting high ratings to instructors of easier courses, such as history and sociology, find Anthony Greenwald, PhD, and Gerald Gillmore, PhD.

?Our research confirmed what critics of student ratings have long suspected?that grading leniency affects ratings,? says Gillmore, director of the University of Washington?s office of educational assessment. ?All other things being equal, a professor can get higher ratings by giving higher grades.?

The study also bolsters previous research, including studies by Cornell University psychologist Stephen Ceci, PhD, that finds that students base their course ratings on how entertaining the instructor is.

The researchers examined student evaluations from 600 classes, representing the range of undergraduate classes offered at the University of Washington. Along with standard questions about the class and the professor, the evaluations included questions about the amount of work required in the class compared with other classes and the grades students expected to receive in the class compared with other classes.

According to Greenwald and Gillmore, students? tendency to rate highest the courses in which they expected their best grades, which were also the classes that required the least work, have several disturbing implications:

? Low student ratings may discourage instructors from setting high standards.

? Students may gravitate toward less demanding, high-grading classes, spurring a drop in the number of demanding courses.

? Grades may be artificially inflated because courses are less challenging.

The researchers recommend reforming the rating system so that students are asked to report not only their satisfaction with the course, but how much they have learned.

Their article is published in the December issue of the Journal of Educational Psychology (Vol. 89, No. 4, p. 743?751).