Effects of past performance and direction of change on bias in performance ratings

Within the framework of a cognitive categorization model of information processing, two factors thought to bias performance ratings were investigated: past performance and direction of performance change. It was hypothesized that (a) past performance categorized as typical would bias ratings of subsequent performance more than past performance categorized as somewhat worse or somewhat better than typical and (b) a performance decrement would bias ratings of present performance more than performance improvement. Subjects in two laboratory studies rated the performance of college instructors from comments written about the instructors. Using a categorical-prototype approach, Study 1 successfully identified the content of five instructor performance categories and developed instructor profiles. Profiles consistently conveyed their intended categorizations. However, neither hypothesis received general support in Study 2. Subjects may have used controlled information processing which reduced the potential for bias. The results are interpreted in light of the cognitive information processing model of performance rating.