Best Practice: Bias-Free Performance Reviews
People, by their very nature, are prone to making unfair judgments about others—even the most open-minded, objective thinkers can fall victim to unconscious biases. Cognitive biases cause inaccurate decisions and perceptions because the human mind processes information so quickly that it often considers the wrong details.
Even though it feels like every situation is evaluated fairly, personal beliefs, experiences, and emotions always influence decision-making—whether we realize it or not.
Biases are common in the workplace, especially when managers are asked to evaluate their team’s performance. With so much to consider, it’s easy to get caught up in irrelevant or incorrect details.
Rater bias doesn’t just impact performance reviews—it can lead to employees feeling undervalued, unmotivated, and even searching for new opportunities where their hard work is recognized.
In this article, you’ll find:
✅ The common rater biases to watch out for
✅ How to prevent them with a modern performance management process
📌 Common Biases in Performance Reviews
Not all biases lead to negative evaluations—some cause employees to be viewed too positively for the wrong reasons. Here’s what to be aware of:
- Strictness Bias
Overly critical managers give low scores across the board. Employees feel disengaged and may leave because they’re not recognized for what they do well.
- Leniency Bias
The opposite of strictness bias—managers give mostly high scores. Employees may enjoy the positive feedback, but it doesn’t help them improve.
- Central Tendency Bias
Managers avoid rating too high or too low, sticking to the middle (like 3s on a 5-point scale). This makes the review meaningless—employees don’t know what they’re doing well or need to improve.
- Contrast Effect
Managers compare employees to each other instead of evaluating them on their own merits.
- Halo/Horns Effect
-Halo Effect: One positive trait, like friendliness, leads to an overly positive review.
-Horns Effect: One negative trait, like poor dress, leads to an unfairly low review.
- First Impression Bias
Managers judge an employee based on their first interaction—like nailing a job interview or, on the flip side, not being the manager’s first choice for the role.
- Similar-to-Me Effect
Managers favor employees they identify with (same gender, race, age group, etc.), leading to biased evaluations and an exclusionary work culture.
- Recency Bias
Managers focus only on what happened most recently—good or bad—and forget the rest of the review period.
- Spillover Bias
The opposite of recency bias—past performance (good or bad) influences current reviews, even if the employee has since improved.
- False Attribution Bias
Employees are blamed or credited for things they weren’t fully responsible for, like a lack of resources or benefiting from a teammate’s work.
🛠️ How to Prevent Rater Bias
Biases are part of human nature, but it’s possible to create a performance management process that minimizes their impact.
Here’s how:
- Set Employee Goals
- Define clear, measurable goals for each employee.
- Avoid generic competencies like “initiative” and “teamwork.”
- Use the SMART framework (Specific, Measurable, Achievable, Relevant, Timely).
- Use Tailored Review Forms and Rating Scales
- Include behavioral and leadership competencies relevant to each role.
- Avoid one-size-fits-all evaluation criteria.
- Use a semi-quantitative scale (e.g., “not effective,” “minimally effective,” “effective,” “highly effective,” “exceptional”) instead of just numbers.
- Add competency descriptions so managers know exactly what each one means.
- Explore the 50 Performance Evaluation Competencies for ideas
- Capture Performance Notes
- It’s unrealistic to expect managers to remember everything from the review period.
- Use a performance management system like Trakstar Perform to document employee progress, setbacks, and achievements.
- These performance notes help avoid recency, spillover, and false attribution bias.
- Collect 360-Degree Feedback
- One rater can be biased; multiple perspectives provide a clearer picture.
- Collect feedback from peers, direct reports, senior leaders, and even external colleagues.
- Learn more about using 360-degree feedback in the Rater Bias Report article.
- Encourage Self-Reviews
- Ask employees to complete a self-review on the same competencies as their manager.
- Use these insights in performance conversations to challenge biases and encourage open dialogue.
- Have Regular Check-Ins
- Don’t just talk about performance once a year.
- Schedule regular one-on-ones so managers understand what employees are working on and how they feel about their role.
- Use these conversations to provide real-time feedback and support.
- Access the Employee Check-In Template to get started.
- Use Data to Uncover Bias
- Even with the right tools, some biases will slip through.
- With Trakstar Perform, you can generate a Rater Bias Report to see how managers are scoring employees.
- Identify who is consistently too strict or too lenient, and coach them on how to fairly evaluate employee performance.
📚 Additional Resources
📄 Setting SMART Goals for Employees