Final answer:
A halo effect occurs when a rater tends to use only one part of the rating scale instead of differentiating among different aspects of an employee's performance in performance appraisals.
Step-by-step explanation:
In the context of performance appraisals, a halo effect occurs when a rater tends to use only one part of the rating scale instead of differentiating among different aspects of an employee's performance.
For example, if a supervisor has a positive impression of an employee's punctuality, they may automatically rate the employee highly in all other areas, such as teamwork or problem-solving, without considering their actual performance in those areas.
By focusing only on one positive aspect, the rater fails to provide an accurate and comprehensive assessment of the employee's overall performance.