If performance information is collected from more than one source, it is likely that there will be some overlap in the dimensions measured. When the same dimension is evaluated across sources, we should not necessarily expect ratings to be similar. Different sources disagreeing about an employee’s performance is not necessarily a problem.

If disagreements are found, a decision must be made regarding the relative importance of the rating provided by each source. Regardless of who rates performance, performance ratings may be intentionally distorted or inaccurate. When this happens, incorrect decisions may be made; employees are likely to feel they are treated unfairly; and the organization is more prone to litigation.

In other words, when performance ratings are distorted, the performance management system not only fails to result in desired outcomes, but also, may lead to very negative consequences for employees and the organization. To prevent these negative outcomes, we need to understand why raters are likely to provide distorted ratings.