Number of Assessment Center Dimensions as a Determinant of Assessor Accuracy

Undergraduates ( N = 131) were trained as assessors, who evaluated the performance of confederates in an assessment center simulation on 3, 6, or 9 dimensions. Number of dimensions significantly affected some assessment center judgments but not others. Ss who rated a small number of dimensions classified behaviors more accurately and made more accurate ratings than did Ss who rated a large number of dimensions. Number of dimensions did not affect the accuracy of assessors' observations nor the discriminant validity of their dimension ratings. Given these results and the findings of others ( Hinrichs & Haanpera, 1976 ; Russell, 1985 ; Sackett & Hakel, 1979 ; Schmitt, 1977 ), developers of assessment centers should limit the cognitive demands placed on assessors by, for example, minimizing the number of dimensions assessors are required to process.