What is Survivor Bias?

During WWII, the United States Army wanted to protect their airplanes and needed to know where to put additional armour. They looked at their bombers, that were returning from the war riddled with bullet holes, and plotted points on a chart to show where the bombers were being shot the most. This image gave them a clear message: ‘bombers are shot more along the tail, body, and wings’ – “Fantastic, we will put the armour there then!” They thought.

Survivor Bias describes our human tendency to focus on the people or things that have passed some sort of selection process, whilst forgetting about other important factors. For example, when considering the successful entrepreneurs that never went to university, we tend to forget about all the unsuccessful ones that did the same. People often incorrectly assume that mobile phones made 10 years ago last longer than modern ones because it is easy to forget about the millions that stopped working along the way.

In our example earlier, the United States Army forgot to consider the sample they were looking at only included the returning bombers, not the ones that had been shot down. The image they had created demonstrated where planes would be shot and still return, thus the image they had created should have actually been used to show where additional armour was not necessary.

How Could Survivor Bias Affect you?

Should you fail to frame your question properly, incorrectly consider your entire sample, or simply be too strongly led by your own optimism and enthusiasm, you may fall prey to Survivor Bias. This Survivor Bias could crop up in any decisions you make that affect your personal life, your team, or products and as such, it is worth spending some time thinking about how it might affect you.

Below we will look at a few common improvements that businesses would want to make and have a look at how and why people might fall foul to Survivor bias, leading them to make bad decisions.

Staff Retention

You have looked at your employee count at the beginning of the year. You have got your number of staff that have left throughout the year. You have identified that you may need to make some improvements. You send out a survey to your employee base and ask them why they have stayed with the company.

Consider that from that survey, every story you are given is a bullet hole in your returning Bomber.

When it comes to improving staff retention, you want to know why people are leaving just as much as why they people are staying and if you don’t include the ex-employees in your sample, you’re not going to get the whole picture. Consistent exit interviews are an excellent way of gathering this information.


If people let all their sales secrets and tactics out then firstly they would not be secrets, and secondly, no-one would bother writing the ‘1000th Sales bible’, at the modest price of £19.99.

Listening to your top salesman is a good idea, but do not forget that you can learn a lot from your under-performers too. Survivor bias encourages us to look at all of our sample when coming to conclusions we act upon, humbly reminding us that it is very unlikely for someone’s success in sales to just be because of a bright smile and a can-do attitude.


Bob’s Brushes have been making toothbrushes for years and want to design a new product. They need to know how to make their bristles stronger as they want to start supplying to vets. They gather all the toothbrush literature they can find but cannot glean any new insights.

Survivor Bias is hindering Bob’s Brushes innovation in this scenario. Consider what the vital selection process was for Bob when researching new ideas: he was only looking at toothbrush literature. Perhaps the answer to Bob’s dilemma could be found in the exciting world of toilet brush research, or pipe cleaner technology?

Mental Health

Start by posing the question: How do I improve my employee’s mental health? Let us swap our WWII bomber for an employee and assume that after surveys and conversations, every complaint or improvement they can suggest is because of a bullet hole in their chassis. If there are enough bullet holes the employee will be “shot down”, but consider for a moment that your sample, your active employees, may simply be the returning planes.

A person is much more complicated than a plane’s body and as an employer, you cannot easily pinpoint the sensitive engines and cockpits of an individual’s life. As an employer, you can and should minimise the number of shots your staff takes at work, but you can find some reassurance in the reality demonstrated by survivor bias, that you are never in full control of whether someone does develop a significant mental health issue. Maybe consider that psychologists and mental health professionals are wartime scavengers, with access to the full sample of shot down planes.

I appreciate that I have leaned very heavily and clumsily on a strange metaphor throughout this text so thank you for bearing with me. Assuming the line between man and machine has already been sufficiently blurred for you, let me leave you with some closing thoughts.


Onwards and Upwards!

As demonstrated above, it will be extremely beneficial for you to be aware of potential survivor biases that affect your decision making in the workplace, or otherwise. The adage around making assumptions holds true here, and the key to recognising survivor bias, is to notice when you are being overly exclusive when posing a question or making investigations.

Often survivor bias will manifest from an individual’s desire to be able to deal with a problem themselves quickly and easily, but know that accepting a little bit of help will pay dividends and often in fact be necessary to really address your issue.


How Kate Underwood HR Can Help You Today?

Lots of issues that arise from the recognition of survivor bias can be remedied with good HR support. As mentioned earlier, thorough exit interviews will help you to get a true understanding of your retention rates; deliberate and consistent job descriptions and appraisals will help to identify the factors leading to high performance, and employment law support will help you to when things do go wrong and you need to show you’ve acted reasonably as an employer.

At Kate Underwood HR, we put the H and the R in “more Human’eR”, so if you want to talk about your own HR needs or have your own ideas on how to deal with identified survivor biases, please feel free to give us a call on 02382 025160 or email [email protected].

We are more than happy to perform free HR health checks on any business, with no obligations afterward, so why not get some free peace of mind and learn where your practices put you as an employer?

Thanks for reading!

Pete 🙂


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