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5 Best Practice Tips for Reducing Rater Bias in Performance Reviews

Posted by Julie • August 3, 2017 (Last modified March 15, 2021) • 5 min read

Effective performance management relies on accurate information from performance reviews. Rater bias undercuts this effort by calling into question the accuracy of these ratings. No one is immune to rater bias, so every HR professional should be aware of its impact.

Biases like the halo effect, the leniency bias, and the “similar to me” effect may artificially inflate ratings. Meanwhile, the horns effect, the strictness bias, and the recency effect can lead to too-low ratings, even for high-performing employees. No HR professional wants to make high-stakes decisions, like promotions, raises, or dismissals, based on inaccurate data. HR has a moral, and legal, imperative to make sure performance review information is high quality.

Luckily, there are solutions. Researchers have identified best practices to dramatically reduce the impact of rater bias on performance reviews. Apply these five strategies to your performance management system to ensure that your employees are receiving fair and accurate ratings that are not colored by rater bias.

1. Build Awareness of Rater Bias

Rater bias affects everyone, but it usually occurs on an unconscious level. This means that most employees will not be aware of their biases, even when biases are dramatically impacting how they rate their coworkers.


When performance appraisal season comes around, invest time in training your staff about the most common rater biases. Making employees aware of bias is the first step towards reducing it.

For most employees, a short training that covers just the highlights is probably enough to do the job. However, senior staff, such as supervisors or managers, often complete performance reviews more frequently. They would benefit from more in-depth training on understanding and reducing their own bias.

2. Use Objective, not Subjective, Ratings

When designing your performance review questions, pick question anchors that ask about observable, objective behaviors. A good example of a top rating might be, “Rarely or never misses deadlines.” This is clearer and more objective than a simple, “Meets Expectations” or “Exceeds Expectations.”

Subjective ratings are not recommended because they are often murky and rely on judgment. A supervisor might check an employee’s records to determine if they have been meeting deadlines. However, if they are asked to make a subjective judgment about personality, style, or attitude, all they can do is go with their gut. That’s exactly where unconscious biases rise to the surface and begin to impact ratings.

3. Reduce Reliance on Memory

We like to think of our memory as a museum filled with well-preserved accounts of our past experiences. Unfortunately, research on memory consistently shows that our memories aren’t always accurate, especially when emotions get involved. The more performance ratings rely on memory, and the longer back raters have to think, the less accurate performance reviews become.

One strategy to reduce reliance on memory is to have more frequent performance reviews throughout the year. This lets raters focus on more recent, more easily remembered events. Try biannual or even quarterly performance reviews rather than just once each year.

Online employee performance reviews, facilitated by quality performance management software, are the ideal way to manage the extra information gathered by more frequent reviews. They simplify the process of collecting and analyzing performance reviews, which minimizes the burden on employees and HR professionals.

A second strategy to reduce reliance on memory is to encourage note taking in between performance ratings. Raters can look back at their notes to remind themselves of positive and negative performance. This reduces reliance on memory, and ultimately improves the accuracy of ratings.

4. Implement 360 Degree Feedback Systems

Even with the above techniques, there is no way to eliminate all bias. Because of this, it is never wise to rely on a single rater for employee evaluations.

Instead, it is best practice to gather performance ratings from multiple sources. This gives you a more complete picture of actual performance while minimizing the impact of any particular rater’s bias.

360 Degree Feedback systems are ideal for for this task. They naturally allow for feedback from a variety of sources, including supervisors, direct reports, peers, and even customers. This provides a wealth of information on employee performance, and grants you more confidence in the accuracy of the review process.

For 360 Degree Feedback to be effective while not being an undue burden, you’ll need performance management software that is up to the task of streamlining your system. Select software that allows for easy reviewer assignment, allows ratings from reviewers outside the company, and allows for anonymous reviews so ratings aren’t impacted by fear of retaliation.

5. Carefully Monitor Performance Feedback Data

Rater bias can often be detected by carefully examining performance feedback data. Using performance management software, keep an eye out for clues that bias may be in play. Look for:

  • Outliers. If an employee has mostly consistent ratings, except for a single rater with much higher or much lower ratings, rater bias may be the culprit. Interpret outliers with extreme caution.
  • Little Variability Across Ratings. If, on the other hand, a single rater seems to have the same ratings for everyone he or she reviews, consider if the strictness, leniency, or central tendency bias is playing a role.

Performance management software is critical for facilitating this kind of analysis. Select software that makes it easy to look at company-wide trends, while maintaining the ability to zoom in on individual employee or individual rater data.

The Best Performance Management Software to Reduce Rater Bias

To effectively minimize the impact of rater bias on your human resource decision making, you’ll need powerful performance management software.

Trakstar includes 360 Degree Feedback, which facilitates quality performance reviews from a variety of sources. Use them to set up online employee performance reviews to streamline the process. Moreover, they make data analysis simple, allowing your HR department to carefully watch for signs of bias.

Performance management software is the key to effective performance reviews. You can trust Trakstar to minimize rater bias in your company.

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