Block inadvertent bias from creeping into reviews

When drafting performance reviews, every manager aims to be fair and consistent. But research shows that, too often, a concept known as “rater bias” can subtly—and inadvertently—influence a manager’s ratings.

This can result in either artificially low or artificially high ratings of employees. Both can discourage employees, hurt morale … and trigger legal liability.

Employees often use performance reviews as ammunition in lawsuits claiming job discrimination based on some “protected” characteristic (race, sex, age, religion or disability status). Courts will pounce on any inconsistent or unrealistic ratings they see in reviews.

Here are the six most common types of bias to be aware of when drafting reviews or other types of feedback:

1. Recency bias

Research shows that managers’ reviews typically put more weight on performance and behavior that occurred most recently. If you rely solely on your memory to evaluate performance, you’re making the appraisal more difficult than necessary—and less effective.

To avoid this type of bias, institute a simple recording system to document employees’ performance and behaviors—both good and bad. This doesn’t need to be sophisticated. Simple notes in a folder or regular e-mails into an Outlook folder will do. Include concrete examples of positive and negative actions.

Focus on recent actions only if they represent a significant decline or improvement. But consider everything employees have done during the entire evaluation period.

2. Leniency and strictness bias

For reasons they may not recognize, some managers offer exceptionally high ratings across the board, even for marginal employees. Maybe they want to avoid confrontations with employees.

On the flip side, some managers are excessively strict, refusing to hand out great reviews, even to great employees.

In both cases, overly strict and overly lenient ratings do a disservice to the employee and open the organization to legal trouble.

Periodically review evaluation guidelines. Ask yourself if you have any preconceived notions about handing out the highest and lowest scores. Ask HR or a fellow manager to review your ratings.

3. The ‘halo effect’

The halo effect occurs when a manager rates an employee’s performance in several areas based on his or her performance in one area.

For example, someone who contributes excellent ideas but performs poorly or average in other duties may receive a good overall evaluation. Or a cocky high performer may receive lower than deserved ratings in several areas because of his attitude. Don’t generalize based on performance in one area.

4. Central tendency bias

This involves managers who tend to rate employees in the middle of evaluation scales—never on either end of the “great” to “poor” scale.

Evaluations work best when managers use all ratings levels, when warranted, to portray strengths and weaknesses.

Remember that most employees perform better in some areas than others. And most departments have poor, average and excellent performers.

5. Compare/contrast bias

Don’t base evaluations on comparisons with co-workers.

When you’ve got a star performer on a team, it’s common to want to compare every other player to that person. But it’s not fair. Instead, rate each person’s performance individually according to the organization’s predetermined performance criteria.

6. Length of employment bias

Studies have also demonstrated that some managers dish out reviews due, in part, to the employees’ length of employment. The longer the tenure, the better the review. Don’t assume that experience automatically equals good performance. Evaluate senior employees as objectively as new hires.

The bottom line: Remember that it’s natural for managers to have different personal feelings about each employee—and have preconceived notions about their performance. But your goal is to separate those personal views about employees from their actual performance, and to offer the most objective and consistent feedback possible.

Phrases never to use during performance reviews

“You’re wrong.” If an employee tries to explain why her job rating should have been higher, don’t slap back with a Trump-like, “You’re wrong.” That will only trigger anger and more confrontation. Instead, turn back to your documented facts of the employee’s performance and say, “I know you disagree, but I believe this evaluation accurately reflects your performance.”

“You did a great job but … ” Whatever comes after the “but” negates the preceding compliment. Don’t directly connect praise with constructive criticism. Instead say, “On the other hand, you can do even better by making these improvements.” Then, cite them specifically.

“I understand.” This phrase can excuse unacceptable performance or behavior by conveying empathy. Avoid it.

“Your position here is solid as long as you keep up the good work.” You may intend such statements to encourage good performance, but they’re legally dangerous because they imply an employment contract that a court could find binding. That limits the organization’s ability to terminate the person if his or her performance declines.