The results of five annual surveys of second year medical students over an eight year period of time (1978-1985) concerning perceptions and attitudes toward public health and a course in preventive medicine and community health are presented. The questionnaire format was a combined fixed alternate and free response type and was structured to require only ten to 15 minutes for its completion. Participation rates were generally high varying from 60.2% (1980) to 93.8% (1985). The majority of students in all years favorably evaluated most components of structure, content and presentation of the course. It was found that opinions about the course can be modified by the introduction of variables that are unrelated to the scope of the quality of the course as occurred in 1979, with a difficult midterm examination. Student anger over this examination was translated and expressed as negative opinion about many other aspects of the course which in other years were highly rated. This finding underscores the vulnerability of surveys of subjective opinion and demonstrates that course evaluations must include other objective aspects in addition to student perceptions.