What Is the "Devil Effect" Bias

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The devil effect bias is the opposite of the halo effect bias. Wheras the halo effect results in inflated employee ratings, the devil effect results in artificially low ratings of an employee. The devil effect comes into play when the rater, or manager generally dislikes, or has little confidence in an employee, and tends to rate the employee as low functioning on all or most of the rating items.

In other words the general opinions of the rater or manager can exert a strong effect even if the particular employee is good at a few of the things refered to by other items.

For example, an employee may be doing very well at sales, but, unfortunately the manager is blinded to this fact by having negative opinions of the employee -- perhaps something as simple as disliking the employees' communication or personal style. So, the manager rates the employee poorly on ALL items, including sales, even if the person is a good salesperson.



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Bacal & Associates was founded in 1992 by consultant and book author, Robert Bacal. Robert's books on performance management and reviews have been published by McGraw-Hill. He is available for consultation, training and keynote speaking on performance and management at work.


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