The moderating effect of raters' opportunities to observe ratees' job performance on the validity of an assessment centre

Previous research has suggested that the quality of judgmental validation c riteria may improve depending on the increase of opportunity for the rater to observe ratees' job performances. This study investigated whether the va lidity of an assessment centre increases with opportunity to observe. Subje cts were engineers and applied scientists from the Research and Development (R&D) units of seven German high-technology companies. A total of 6 personality scales, 10 cognitive ability tests and 9 work samp les was administered to 155 subjects. Performance appraisals were collected from their supervisors. Assessors were trained organizational psychologist s who were not members of the participating organizations. A total score (' assessment centre score') was computed by averaging the 25 predictors after standardization of each predictor. The (uncorrected) validity of this asse ssment centre was r = 0.37. In addition, opportunity to observe (i.e. amoun t of time the performance rater was the ratee's supervisor) emerged as a mo derator: for example validities were r = 0.09 (opportunity to observe less than or equal to 2 years) and r = 0.50 (opportunity to observe > 2 years).