Prior research has shown that frame-of-reference training increases the accuracy of performance appraisals more than rater error training (e.g. Hedge & Kavanaugh, 1988). Frame-of-reference training facilitates the learning of accurate performance standards (e.g. Athey & McIntyre, 1987), while rater error training results in the introduction of biased response sets (e.g. Bernardin & Fence, 1980). Bernardin and Buckley (1981) recommended that individuals who possessed an idiosyncratic rating style or aptitude would benefit especially from frame-of-reference training. However, no research to date has investigated the interaction of rating style and frame-of-reference training effects. The hypothesis of the present study was that rating accuracy and reliability would improve for idiosyncratic raters in frame-of-reference training, while the effective rating style of normative raters would not change. Further, rater error training should impair normative raters’ accuracy and reliability, while it should not affect the ineffective rating style of idiosyncratic raters. However, the results of this study failed to show the rating aptitude-training-time interaction with accuracy. Some support was found for a rating aptitude-training-time interaction with reliability as a result of rater error training. This study replicated previous findings that frame-of-reference training increased rating accuracy and reliability. Frame-of-reference training improved the Cronbach (1955) measures of differential elevation, stereotype accuracy, and differential accuracy. / Master of Science