Common Rater Errors

Rater errors are errors in judgment that occur in a systematic manner when an individual observes and evaluates another.

Personal perceptions and biases may influence how we evaluate an individual’s performance. What makes these errors so difficult to correct is that the observer is usually unaware that they are making them.


When we understand the errors and how they occur, we are able to take steps to minimize them.

Consistency Errors

• Halo Effect – The tendency to make inappropriate generalizations from one aspect of a person’s job performance. This is due to being influenced by one or more outstanding characteristics, either positive or negative.

• Leniency – The tendency to evaluate all people as outstanding and to give inflated ratings rather than true assessments of performance.

• Central Tendency – The tendency to evaluate every person as average regardless of differences in performance.

• Strictness – The tendency to rate all people at the low end of the scale and are overly critical of performance.

• Contrast Effect – The tendency for a rater to evaluate a person relative to other individuals rather than on-the-job requirements.

• First Impression Error – The tendency for a manger to make an initial favorable or unfavorable judgment about someone, and then ignore subsequent information that does not support this impression.

• Similar-to-Me Effect – The tendency to more favorably judge those people perceived as similar to the leader.

Minimizing Rater Errors

Since rater errors can seriously undermine the value of the Performance Development Process, it is important to work on avoiding them.

Questions to Ask Yourself to Avoid Rater Errors

• Am I basing my rating on documentation of my observations of the Employee’s behavior, or am I making judgments based on my perceptions?

• Am I looking at each of this Employee’s competencies separately, or have I generalized about their performance?

• Have I looked at this Employee’s competencies over time, or have I generalized according to initial perceptions of them?

• Have I recognized any biases I may have so I do not let them influence my judgments?

• Have I rated this Employee on their actual behavior, or have I rated them compared to other individuals?