Assimilation and contrast effects in performance ratings: Effects of rating the previous performance on rating subsequent performance.

This study examined the effects of rating previous performance on ratings of subsequent performance. Participants (N = 214) reviewed a performance script depicting either good or poor performance and then reviewed and rated another script depicting average subsequent performance. Approximately half of the participants rated the previous performance immediately after reviewing it, and the other half did not rate the previous performance. As expected, a Performance Level x Existence of Ratings interaction was found. When they had not rated the previous performance, raters were biased in favor of recalling behaviors consistent with their previous impressions, suggesting an assimilation effect. However, when they had rated the previous performance, raters provided ratings inconsistent with their previous ratings, suggesting a contrast effect. These effects were stronger for ratings from a behavioral expectation scale than for those from an ability rating scale.