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How to reduce cognitive bias in performance reviews

For many, performance reviews are the foundation of performance management. But they simply don't work. They rely on outdated metrics and subjective feedback. That’s why we recommend adopting performance conversations rather than performance appraisals. And here's how that reduces any bias in the performance review process and 1:1 meetings.

Conscious bias versus unconscious bias in performance reviews

Before we get into how bias reduces the effectiveness of performance reviews, we need to talk about conscious and unconscious bias. Both types can interfere with your ability to review employee performance effectively. But one can be a lot harder to address than the other.

Conscious biases

Conscious biases are, arguably, easier to deal with because they're rooted in things an individual actively believes. While racist and sexist beliefs can still be held unconsciously, overt bigotry is an example of conscious bias.

Unconscious biases

Unconscious bias tends to crop up when we need to make quick decisions. Snap judgements are based on your cumulative knowledge, beliefs and experiences. No matter how objective you think you are.

A classic example is this riddle. A father takes his son into hospital, only to find that the attending surgeon cannot operate because the child is also theirs. Many people struggle to find the answer to this, because they assume the surgeon to be male. So it's the unconscious biases that often proves trickier to deal with. That's bcause you can still hold these beliefs while having the best of intentions towards your employees.

The different forms of cognitive bias in performance reviews

The brain is marvellous in in its processing power. Despite this, the human mind still has limitations and still cuts corners to work more efficiently. So the reason that humans have biases is down to how our brains categorise information.

Daniel Kahneman won a Nobel Prize for his research into cognitive biases. Other researchers, such as Dan Ariely or Paul Slovic, have also contributed a lot to this field. As a result, we know there are potentially hundreds of biases that can impact workplace decision-making.

Here are 5 of the most relevant and influencing bias found in performance reviews.


Anchoring is when you place too much importance on an initial piece of information you receive. Regardless of how relevant it turns out to be in the decision-making process. For instance, a new hire was late a few times in their first week. They'd just moved to a brand new city and were still finding their feet. This initial faux pas may colour your perception of that employee's time management skills. Even as they become perfectly punctual once they've settled in.

Availability heuristic

The individual makes an important decision based on the information that's easiest for them to recall. Not necessarily the most relevant facts. For example, you might base the results of a performance review on their performance in recent weeks. This can be problematic, especially if a major life event has just occurred. It can result in the employee's achievements at other points in the year being overlooked. This recency bias during a performance review can have damaging consequences. If your employees don't feel like their hard work is being recognised, they're liable to become disengaged over time. This is why having an effective framework for feedback between performance reviews is essential.

The Dunning-Krueger effect

In the words of Patrick Star from Spongebob, "Dumb people are always blissfully unaware of how dumb they really are'. And that's basically what the Dunning-Krueger effect is. The less informed you are about a subject, the more likely you are to think you understand it. And there's nothing more irritating than being talked down to by a layperson about your primary area of expertise. If you manage people with highly specialised skill-sets, the Dunning-Krueger effect is a major bias you need to watch out for in performance reviews. This is why trust plays such an important role in the workplace. You need to be able to defer to the knowledge of your team and peers.

Representative heuristic

This is essentially the stereotyping bias. This bias causes people to make judgements based on pre-existing assumptions. Representative heuristic bias in the hiring process would mean hiring someone who fits your stereotype for the sort of person doing that job. If you think all IT personnel are nerds with beards then you'll end up hiring people who fit that mould. This is a particularly risky bias to leave unaddressed, as it can easily move into the realms of discrimination. Case in point, an employee is snubbed because their manager thinks working mothers won't perform well in high-pressure leadership roles.

Regression to the mean

This is basically the act of making predictions based on faulty information that fails to account for someone's average rate of performance. An example from Khaneman's research is that of Israeli pilots. Instructors preferred criticism to praise, as they noticed that pilots seemed to perform worse after being praised, but better after being criticised. Khaneman realised that this was not the case, and that pilots regressed to their mean rate of performance regardless of praise or criticism.

Reducing the impact of bias in performance reviews

It's impossible to do away with unconscious bias entirely. It's a result of the brain trying to work as efficiently as possible to help you excel physically and socially. But managers have a duty of care to their employees. And part of that duty is mediating their unconscious bias in performance reviews to the best of their ability.

Ultimately, the best cure for bad performance management is the same as any poor management practice. Emphasise workplace education, especially proper management training. Too many people end up in leadership roles without any formal training. And this opens the door for ineffective or discriminatory leadership, unconscious or otherwise.

If you're worried about your own objectivity as a manager, try prefacing your performance reviews with 360 feedback. Getting insight from an employee's colleagues, as well as anyone else who's managed them, can help to cover your blind spots. They'll also provide more comprehensive insight for the employee to use as a basis for self-improvement. You may even realise that an employee you thought was just okay has actually been the secret superstar of your entire department the whole time.

Get more from our latest best practice guide: How to have more effective performance conversations. Download your copy below 👇