A halo effect occurs when the evaluator generalises one positive aspect of a person's performance (e.g. cooperation) to other aspects (e.g. sense of responsibility). A single, positive aspect influences all other aspects.
This occurs when the evaluator generalises by associating one negative characteristic of the 'appraisee' (e.g. clothing style) with all other aspects and characteristics (e.g. collaboration). Here, a single negative aspect influences all other characteristics.
Contrast effect occurs when an evaluator is influenced by previous impressions. For example, if evaluators have just appraised two poorly performing employees, he or she will then appraise an average employee more positively, because of the contrast with the two previous appraisals. The reverse is also possible. An employee who performs averagely and is evaluated after two good performers may receive a very poor evaluation.
Stereotyping occurs when the evaluator attributes personality traits to a candidate on the basis of externally observable characteristics. The assessor then judges character and personality traits rather than work behaviour and performance. Or the evaluator on preconceptions about an employee, instead of actual work behaviour and performance.
Assessors often tend to form their overall impression of a person within minutes. Sometimes this first (un)favourable impression can continue to play a role, to the extent that new information will hardly affect the assessment.
Some evaluators have a tendency to consistently overrate. The evaluator may be influenced by the prospect of continuing to work with the evaluated person. Or it could be that they don’t want the department to get a bad name, and therefore chooses to assess more positively than is warranted.
Some appraisers have a tendency to systematically give low ratings. Their high expectations are difficult to meet.
Some assessors systematically choose the central point on the rating scale and therefore avoid extreme positive or negative judgements. This results in no distinction between high-quality employees/candidates and those who might perform less well.
Some appraisers tend to appraise employees better if they resemble the appraiser in behaviour and personality. A young assessor may, for example, score younger candidates higher.
This occurs when the evaluators perceive themselves as less biased than others.