Omission Bias

You miss one hundred percent of the shots you don’t take.

Wayne Gretzky said that, the famous ice hockey player, and it’s one of my favourite quotes. Not only because it’s true, but because it gives us a perfect example of how omission bias affects us every single day.

For some people, omission bias is a difficult cognitive bias to understand and appreciate. The effect it has on everyday life is subtle, insidious, easy to miss. So I’m going to use Gretzky’s quote to make understanding it just a little bit easier.

In a nutshell, omission bias is the reason why we don’t take the shots in the first place. Omission bias is the mental tendency to prefer inaction to action, to judge doing nothing as better than doing something, even when the outcome is identical.

Mentally, we judge harmful actions to be worse than inaction, than omissions. The majority of us would judge taking a shot and missing as worse than not taking the shot at all. Yet in this example, both shooting and missing and not shooting at all have exactly the same consequences. You don’t score. The result is identical. We just evaluate internally that action is worse than inaction.

In society, harmful actions are generally judged worse than inaction, even if the result is the same. Here’s a quick example. There’s a small old country pub not too far from me called The Plough that does a great pint of really good English beer. If you walk to the right of the bar, there’s a one inch step in the floor that’s difficult to see but easy to trip on. If you’re not a local at the pub, or if you’ve had too many pints, then that step’s going to get you every time.

There are a few locals who sit at the bar and watch people who are new to the pub come in. They find great amusement in watching them trip up.

The thing is, deliberately tripping someone up is generally seen as morally worse than just standing back and letting someone trip over. The consequences are the same. Someone trips and falls. But actively tripping someone up is malicious. It could even be judged as assault. Seeing someone trip over, though, that’s often seen as entertainment, especially for a few of the locals at the bar.

In life, you generally don’t succeed at anything unless you try. But omission bias is one of the things that stops us trying, because we judge not trying as a better excuse than trying and failing. Morally, not trying is seen as the lesser crime, easier to cope with, generally more acceptable internally and to others. Yet the result is the same.

I run vaccination clinics. Some vaccinations can have side effects. These side effects, however, are orders of magnitude less likely to cause harm than the effects of the disease itself if you were to catch it. But for parents, especially those with young babies, doing something that theoretically could harm your child, even though the risk is really, really low, having the vaccination, is judged by them as being worse than taking the risk of letting your child be vulnerable to the diseases they would have been protected against.

Omission bias is one of the factors behind why some parents choose inaction and decide not to vaccinate their children. It’s rarely the whole story on its own; trust in the information they’ve been given, past experience, and what people around them are doing all play a part too, but the pull towards inaction when the alternative is doing something that feels risky, however small that risk actually is, is a real part of the picture.

Sometimes in medicine, omission bias isn’t just theoretical. It’s real life and death. There’s a condition called an aortic aneurysm. This is a dilatation of the largest artery in the body. Sometimes these aneurysms get too big and burst. If your aorta bursts, the odds of survival for those who make it to theatre are genuinely poor, even with emergency surgery.

I’ve seen surgeons take these patients to theatre even when all seems lost. Having the courage to fail, they take action, and this is why these patients eventually walked out of the hospital a few weeks later. Whereas omission bias, backed by statistics, audits and preoperative scoring, could push some surgeons not to operate at all.

Sometimes in life, sometimes you just need to give it a go.

The surgeons who did operate wouldn’t be successful in every case. Some of their patients would die in theatre. These surgeons would also then have a much higher operative mortality rate than their peers, the surgeons who make the choice not to operate. Deciding not to operate can be the right, defensible clinical call in a genuinely hopeless case, but it’s worth noticing how easily the safer-looking choice, on paper, can also be the one that never gives a patient a chance.

Mostly, however, omission bias is not life and death and doesn’t necessitate an instant decision. Instead, it can often be insidious. Its effects are slow. Omission bias creeps up on you as you make a habit of taking inaction over action. Inaction is often intangible. It can be a series of little excuses in your life, the little things that only you know you aren’t doing, the options you don’t take, the times you turn away from opportunity or don’t step up to the challenge.

Not arriving for the interview just because you may not get the job. Not picking up the phone to talk to a potential client just because they may say no. Not talking to the person you’re attracted to just in case you get rejected. All good examples of this cognitive bias at work.

The real problem is that omission bias feels morally more defensible when explaining your inactivity to yourself and others. Listen for the giveaway phrases;

“It’s really hard.”

“Loads of people apply.”

“He’s really good looking, he’ll never talk to me.”

These are all indications of omission bias at work.

Omission bias is why you fail to turn up, fail to follow through, fail to take action. Listen for the small excuses you keep telling yourself before you decide to give something up.

Remember, even if you fail, the result is the same as not taking action. You don’t get what you wanted. The only difference is that with action and failure, at least you learned something. With inaction, you learned nothing except how to get better at making excuses.

Morally, it’s always going to be more acceptable for you to do nothing. But unfortunately, that state of mind is never going to get you anywhere in life, and certainly not anywhere near your full potential.

Sitting back feels better than doing what you need to do. Not taking action will always give you more comfort. Omission bias worsens your procrastination. Omission bias takes away your motivation to take action.

Omission bias keeps you on the sofa. It keeps you in your comfort zone. You probably don’t even realise the cumulative effect it has on your life until all of those little excuses add up.

I had a patient, call him Mark, who wanted to change careers. He’d been in the same job for fifteen years, hated it, knew exactly what he wanted to do instead. He’d researched it thoroughly. He knew the qualifications he needed. He knew people in that industry. He had a clear path forward.

But he didn’t take it.

Every few months he’d come in, stressed about work, talking about how much he hated his job, how unfulfilling it was, how he was wasting his life. Every time I’d ask, “Have you started the training yet?”

“Not yet. It’s expensive.”

“Have you looked into payment plans?”

“Not yet. I’ve been too busy.”

“Have you reached out to anyone in that field?”

“Not yet. I don’t want to bother them.”

Five years later, he’s still in the same job. Still hating it. Still talking about changing. Still not doing anything about it.

That’s omission bias. The cumulative effect of choosing inaction over and over until inaction becomes your default setting. Until not trying feels safer than trying. Until the risk of failure feels more threatening than the certainty of staying stuck.

The fact is, you may have nothing to lose by trying. But you’ll always lose if you don’t.

You miss one hundred percent of the shots you don’t take. That’s not just about hockey. That’s about your career. Your relationships. Your health. Your dreams. Every opportunity you walk past because it might not work out. Every conversation you don’t have because they might say no. Every goal you don’t pursue because you might fail.

The result of not trying is guaranteed. The result of trying is uncertain. Omission bias makes you prefer the guaranteed nothing over the uncertain something.

But here’s what omission bias doesn’t tell you. Every successful person you admire, every achievement you respect, every breakthrough you’ve heard about, they all required someone to take action despite the possibility of failure. They all required someone to overcome omission bias and take the shot anyway.

Nobody ever achieved anything by not trying.

Nobody ever built anything by staying still. Nobody ever grew by playing it safe every single time.

So start noticing your omission bias. Catch yourself when you’re choosing inaction because it feels safer. Ask yourself, what’s the actual worst case scenario if I try and fail? Then ask yourself, what’s the actual worst case scenario if I never try at all?

Usually, you’ll find that not trying is actually the bigger risk. Because staying stuck is guaranteed. Trying at least gives you a chance.

Further reading

• Ritov, I., & Baron, J. (1990). Reluctance to vaccinate: Omission bias and ambiguity. Journal of Behavioral Decision Making, 3(4), 263-277.
• Spranca, M., Minsk, E., & Baron, J. (1991). Omission and commission in judgment and choice. Journal of Experimental Social Psychology, 27(1), 76-105.
• Asch, D. A., Baron, J., Hershey, J. C., Kunreuther, H., Meszaros, J., Ritov, I., & Spranca, M. (1994). Omission bias and pertussis vaccination. Medical Decision Making, 14(2), 118-123.
• Samuelson, W., & Zeckhauser, R. (1988). Status quo bias in decision making. Journal of Risk and Uncertainty, 1(1), 7-59.
• Kahneman, D. (2011). Thinking, Fast and Slow. Farrar, Straus and Giroux.