When supervisors rely on their personal expectations to assess employee performance, they are committing which error?

When supervisors rely on their personal expectations to assess employee performance, they are committing the error of bias. This type of error occurs when a supervisor’s personal feelings or preferences influence their judgment, leading to unfair evaluations of an employee’s performance. Such biases can result from preconceived notions, stereotypes, or favoritism, ultimately affecting the accuracy of the performance assessment. Recognizing this error is crucial for ensuring a more objective evaluation process, allowing supervisors to base their assessments on actual performance metrics and behaviors rather than personal opinions or expectations.

In contrast, the other errors mentioned imply different sorts of evaluation mistakes. The error of contrast involves comparing an employee's performance to that of others rather than to set standards, the error of central tendency refers to rating all employees as average, and the error of leniency signifies a tendency to rate employees more favorably than deserved. Each of these has its own implications for how performance appraisal can be distorted, but the specific reliance on personal expectations is best encapsulated by the concept of bias in assessments.