How reliable and valid is 360 degree feedback?

A study on the patterns of rater accuracy shows that length of time that a rater has known the person being rated has the most significant effect on the accuracy of a 360-degree review. The study shows that subjects in the group "known for one to three years" are the most accurate, followed by "known for less than one year," followed by "known for three to five years" and the least accurate being "known for more than five years." The study concludes that the most accurate ratings come from knowing the person long enough to get past first impressions, but not so long as to begin to generalize favorably (Eichinger, 2004).

It has been suggested that multi-rater assessments often generate conflicting opinions, and that there may be no way to determine whose feedback is accurate (Vinson, 1996). Studies have also indicated that self-ratings are generally significantly higher than the ratings of others (Lublin, 1994; Yammarino & Atwater, 1993; Nowack, 1992).