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Avoiding Common Rating Errors

Last updated on Jul 24, 2019

To be fair and objective, a Performance Assessment must be based on the employee’s job-related behavior, not on the employee’s personal traits and not a comparison to other employees.

This list gives the type of rating error, followed by suggestions of what to do (or not do):


Contrast effect

What Not to Do

  • Don’t evaluate people in comparison with others. “No, he doesn’t really deserve an ‘Outstanding’ rating, but compared to the other employees, he really stands out.”

What to Do

  • Do rate them against the standards for the job.

First impression

What Not to Do

  • Don’t let your initial positive or negative judgment of an employee color your later Performance Assessment. A new supervisor noted one employee who was going through a divorce performing poorly. Within a month, the employee’s performance had returned to its previous high level, but the supervisor’s opinion of the person’s performance was negatively affected by the initial negative impression.

What to Do

  • Do weigh evidence fairly.

Halo/horns effect

What Not to Do

  • Don’t make inappropriate generalizations from one aspect of an employee’s performance to other areas of that person’s performance. David was outstanding in his ability to repair equipment. His excellence in this area led his supervisor to rate him highly in unrelated areas where his performance was mediocre.

What to Do

  • Do look at all aspects of your employee’s work.

Similar-to-me effect

What Not to Do

  • Don’t rate people who resemble you more highly that you rate others. Marge, a single mother, had worked hard and been promoted to supervisor. She unconsciously rated several women who were also single parents higher than their performance warranted.

What to Do

  • Do respect differences in talents among your staff.

Central tendency

What Not to Do

  • Don’t rate employees in the middle of the scale if their performance clearly warrants a significantly higher or lower rating. Bill’s desire to avoid conflict led him to evaluate all employees he supervised as “Satisfactory.”

What to Do

  • Do be honest – it’s only fair!

Negative or positive skew

What Not to Do

  • Opposite of the central tendency. Don’t rate employees higher or lower than their performance warrants. “No one in my department will get higher than ‘Satisfactory’ because I want them to have something to strive for.”

What to Do

  • Do be honest – it’s only fair!

Recency effect

What Not to Do

  • Don’t allow minor, recent events to have more influence on the rating that those occurring throughout the review period. Because Max doesn’t keep notes of the overall performance or important incidents of his employees’ work, he can’t remember examples from more than two months ago when he sits down to do their performance assessments.

What to Do

  • Do keep a file for your employee and drop notes into it throughout the year.

Stereotyping

What Not to Do

  • Be careful not to generalize about members of a group and ignore individual differences. Although Joe is the youngest staff member in the unit, he’s one of the most dependable. However, Maria rates the older, more experienced staff higher than Joe because he has fewer years in the job.

What to Do

  • Do recognize individual differences.

Frame of reference error

What Not to Do

  • Be careful not to compare an employee’s performance to your own personal standards.

What to Do

  • Do rate your employee based on the job description or written performance standards. Peter rates Conrad as “Satisfactory” on attendance. Although Conrad has used his leave time appropriately, Peter feels that only 100% attendance warrants a higher rating.