Hindsight bias is the tendency to perceive past events as more predictable than they actually were. Due to this, people think their judgment is better than it is. This can lead them to take unnecessary risks or judge others too harshly.

Because people feel that they “knew it all along,” they overestimate their ability to foresee the outcome of future events, such as medical errors, sport scores, or election results.

What is hindsight bias?

Hindsight bias is a type of cognitive bias that causes people to convince themselves that a past event was predictable or inevitable. After an event, people often believe they knew the outcome of the event before it actually happened.

In reality, people usually consider many different scenarios of what might happen in the future, but there’s no way to be certain which one of them will ultimately materialize. Regardless of which scenario plays out, people become convinced that “they saw it coming.”

Hindsight bias is more likely to occur when the outcome of an event is negative rather than positive. This is consistent with the general tendency people have to pay more attention to negative outcomes of events, known as negativity bias.

Hindsight bias, for instance, might cause us to think that we “knew” a couple in our social circle would break up. This is because our current knowledge allows us to easily re-interpret any past disagreements or questionable behavior as a sign of trouble.

Why does hindsight bias occur?

Hindsight bias occurs as a result of our effort to make sense of an outcome. During this process, we essentially “rewrite the story,” focusing on certain factors and disregarding others.

Three different processes are involved in hindsight bias (these can occur independently or together):

• Memory distortion or “I said it would happen.” Memory distortion is the misrecollection of our earlier judgments. We often misremember past events or information in such a way that they agree with what we already know. This distorted recall also factors into confirmation bias and the availability heuristic. In other words, knowing the outcome makes that outcome more available to us, which means we overestimate how probable the outcome was in the first place.

• Inevitability or “It had to happen.” This involves beliefs about how the world works and what caused an event. In general, people like to think that the world is an orderly place. We strive to maintain this idea of order by drawing on cause-and-effect relationships to explain events. With the information we have at the present moment, it’s easy to see an event as predetermined or inevitable, and this aligns well with how we like to view the world.

• Foreseeability or “I knew it would happen.” This occurs when we retrospectively think that we were able to foresee or predict the end result (the “I-knew-it-all-along” effect). It is easy to understand an event in retrospect, when all the information is available to us. Because it’s easy, we feel certain that we had this understanding all along. This part of hindsight bias relates to the availability heuristic.

What is the impact of hindsight bias?

Hindsight bias causes people to think that certain (negative) outcomes were far more predictable and avoidable than they were in reality. This can have both negative and positive consequences.

• Hindsight bias can become a decision trap because it leads to a flawed assessment of the past. If we have a false idea about how accurately we predicted the outcome of past events, we become overconfident. This has implications for the quality of our future decisions.

• Failure to be surprised by an event prevents us from learning from it. If we have the feeling that “we knew it all along,” it is unlikely that we will take the time to reflect and try to understand why our predictions at that time were wrong.

• Hindsight bias will likely cause us to judge others unfairly for not having been able to foresee past events. This can lead us to criticize the quality of other people’s decisions in the past, using the information available to us at present.

• However, hindsight bias can also work to our advantage. Studies have shown that the same sense-making process that produces hindsight bias can reduce the pain of negative emotional events. In other words, we can comfort ourselves by saying “I knew this would happen.”

• Some studies propose that we may learn from hindsight bias without realizing it. According to this view, hindsight bias is the consequence of our ability to update previously held knowledge. This is a necessary process in order to prevent memory overload and allow our brains to function. Updating allows us to keep our knowledge more coherent and to draw better inferences.

Hindsight bias examples

Entrepreneurs who don’t see their plans succeed often exhibit hindsight bias.

In medical malpractice lawsuits, jurors need to factor in hindsight bias when deciding whether a doctor did the best they could with the knowledge they had at the time.

How can we reduce hindsight bias

Hindsight bias is part of human nature, but there are steps you can take to reduce it:

• First and foremost, acknowledge that we all have biases. Especially when you are thinking about the past, be aware that hindsight bias may influence your perception.

• Track your thoughts regarding possible outcomes in a decision journal. Documenting what you expect to happen allows you to keep a record of what you were thinking at the time you made the decision. By reviewing it afterwards, you will be able to see how accurate your forecast was, but also where it went astray.

• Use the “consider-the-opposite” strategy. Avoid the urge to view past events as having been inevitable by examining all other possible outcomes. With this strategy, we are forced to consider how outcomes that did not occur could have occurred. Raising our awareness of other possible explanations and causal links is an effective debiasing technique.