A new look at within-source interrater reliability of 360-degree feedback ratings

This study investigated within-source interrater reliability of supervisor, peer, and subordinate feedback ratings made for managerial development. Raters provided 360-degree feedback ratings on a sample of 153 managers. Using generalizability theory, results indicated that little within-source agreement exists; a large portion of the error variance is attributable to the combined rater main effect and Rater x Ratee effect; more raters are needed than currently used to reach acceptable levels of reliability; supervisors are the most reliable with trivial differences between peers and subordinates when the numbers of raters and items are held constant; and peers are the most reliable, followed by subordinates, followed by supervisors, under conditions commonly encountered in practice. Implications for the validity, design, and maintenance of 360-degree feedback systems are discussed along with directions for future research in this area.