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A. Halo/Horns Effect
The Halo effect is the tendency to generalize from one specific positive employee trait
to other aspects of the individual’s performance. For instance, a person who is always
willing to help other workers may receive inappropriately high ratings on other related
job factors. The Halo effect tends to blind the supervisor to shortcomings in the person
being evaluated.
The Horns effect, on the other hand, occurs when a particular negative trait or behavior
blinds the supervisor to strengths of the individual being evaluated. An example here
might be a case where a person who consistently argues with the supervisor over job
assignments is rated down on all job factors because of his/her argumentative nature.
The following suggestions can increase objectivity and help prevent this kind of error:
• Consider whether the person being evaluated has done anything unusually good
or bad in the last few months. Either situation can color your thinking.
• Ask yourself whether you feel the person has a particularly pleasant or
unpleasant personality and whether this might be influencing your opinions
regarding their job performance.
• Make certain that you are familiar with the job factors being rated – how they
differ from one another and why they are important.
• Maintain a performance log.
B. Central Tendency Bias and Leniency Errors
Central Tendency Bias errors occur when the supervisor does not use either the high or
low end of the performance evaluation scale. This means that most, if not all, the
ratings end up falling in middle of the scale. If over 90 percent of the ratings are in the
middle category, it is likely that this type of error has occurred.
Positive and Negative Leniency refers to the frame of reference used when rating.
Positive Leniency is the tendency to be an “easy grader” and is demonstrated by giving
too many high ratings. If more than 20 percent of your ratings are in the top two rating
categories (“exceeds expectations” and “outstanding”), you may be rating too easily.
Negative Leniency is the opposite and results in a disproportionate number of low
ratings. If more than 20 percent of your ratings are in the bottom two rating categories
(“needs improvement” and “unsatisfactory”), you may be rating too harshly.
Some ways to reduce Central Tendency Bias and Leniency Errors include:
• In cases where you have given an employee a “satisfactory” rating, make
certain that you are rating on the basis of knowledge concerning the
individual’s performance.
• Remember that most employees either “exceed expectations” or “need
improvement” in at least a few job factors. Keep in mind that few employees
are “outstanding” or “unsatisfactory” at everything.