Errors in Thinking: 9 Common Cognitive Biases

As we prepare for those post-results analysis meetings and thorny performance management conversations, I thought it’d be helpful to outline some common cognitive biases that get in the way of clear and rational thinking.

1. Social Proof

We are more likely to support an idea if we are aware that many other people also support it, particularly when the circumstances are unclear or uncertain.

The SLT and I are in agreement that the GCSE results have greatly exceeded expectations.

2. Groupthink

We have a natural tendency to align our thinking with what we perceive to be the group consensus, even if we are unsure or disagree, in order to avoid standing out and appearing to be a dissenter.

So, any objections to continuing with ECDL next year?

3. Hindsight Bias

After something significant has happened, good or bad, we trick ourselves into believing that the preceding chain of events was foreseeable.

I did warn you that our boys wouldn’t write well on Romeo and Juliet.

4. Fundamental Attribution Error

Where results are concerned, we overestimate the influence of individuals and fail to fully consider the impact of external, situational factors.

You will be held to account for the poor grades your class achieved.

5. Overconfidence Effect

We consistently overestimate our ability to make accurate predictions, even if we possess a reasonable amount of expertise.

I believe that at least 90% of students in 11C will achieve a grade 7 or above.

6. Sunk Cost Fallacy

The more we invest in a particular venture (time or money, for example), the greater the urge becomes to continue with it – even if failure is imminent.

We should run more compulsory Saturday revision sessions because results aren’t getting better.

7. Confirmation Bias

We often use new information to reinforce our existing ideas and beliefs and we tend to filter out information that is incompatible or contradictory.

Grammar schools do aid social mobility because disadvantaged students who attend them tend to perform well.

8. Self-Serving Bias

We are more likely to attribute the successes we enjoy to our own actions, whilst blaming failures on external factors.

The Ofsted report is clearly unfair because it fails to credit the good work we’ve done over the past two years.

9. Information Bias

We tend to believe that if we have lots of information to call upon, even if it’s an excessive amount, we will be able to make better decisions.

Your data packs are ready for analysis and your thirty-five page reports should be prepared by the end of the week.


That’s it for now.  Best of luck to all on GCSE results day and beyond.

Thanks for reading –


Find blog post on My Teaching: Nine Things I’ve Changed here

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