Tips for Managers: Avoiding Common Rating Errors
In order to build trust in the performance management process it is important that ratings accurately
reflect employee performance. Avoiding rater bias can be achieved through a better understanding of
the university’s rating scale. Below is a list of common rating errors to keep in mind:
Attribution: Tendency to attribute performance to external causes.
Central: Majority of individuals rated in the middle. Managers who display central
tendency tend to ignore or suppress differences. This tendency, which produces ratings
that do not distinguish between employees, damages morale and makes decisions for
pay for performance, promotions, or training difficult to justify. Avoid this tendency by:
● Documenting observable behavior over the entire performance cycle;
● Ask yourself if you are seeing the person’s behavior objectively. Seek behavioral
examples from others.
Comparison: Tendency to rate people in comparison to other individuals instead of
documenting performance goals and competencies. This tendency can be particularly
unjust when comparing a person to someone else who is an extraordinarily high
performer. Avoid this tendency by:
● Establishing clear SMART performance goals at the start of each performance
cycle, and
● Evaluating performance against those goals.
Halo/Horn: High (or low) rating given to an individual based on a single performance
goal or competency. This effect is also demonstrated if you let an overall global
impression of the employee influence the ratings. It often occurs with employees who
are friendly or unfriendly toward the manager or who are especially strong or weak in
one skill. Avoid the Halo/Horn effect by:
● Establishing clear and specific standards;
● Maintaining good documentation of employee performance over the review
period;
● Keeping things in perspective in terms of frequency, significance in the overall
picture, and representation of the person’s overall performance;
● Identifying specific behavioral examples which support your ratings; and,
Asking yourself if you have overemphasized aspects of the person’s performance you
find particularly admirable or irritating.
Leniency: Majority of individuals rated at the high end of the scale. In order to avoid
this bias, measure performance against established standards and expectations that are
reasonable and attainable. Compare your ratings with peers. Are your ratings
significantly higher than the ratings of others? Don’t be afraid to provide honest, fair,
constructive ratings.
Primacy: Ratings reflect only initial observation of behavior. It is often hard to
overcome our first impressions of someone’s behavior and we must challenge ourselves
to notice behaviors that support other impressions. Avoid this tendency by:
