Overconfidence Bias in Decision Making
Confidence in a prediction can exceed the evidence supporting it. The Heaths illustrate this with rejected business opportunities and a study reporting a 40% error rate among diagnoses made with complete certainty. Their lesson is to examine uncertainty before committing to a forecast.
THE IDEA
Overconfidence in Predictions
What use could this company make of an electrical toy?
—William Orton, president of the Western Union Telegraph Company, in 1876, rejecting an opportunity to purchase Alexander Graham Bell’s patent on the telephone
The story begins on January 1, 1962, when a young four-man rock-and-roll group named the Beatles was invited to audition in London for one of the two major British record labels, Decca Records. “We were all excited,” recalled John Lennon. “It was Decca.” During an hourlong audition, they played fifteen different songs, mostly covers. The Beatles and their manager, Brian Epstein, were hopeful they’d get a contract, and they waited anxiously for a response.
Eventually they received the verdict: Decca had decided to pass. In a letter to Epstein, Dick Rowe, a prominent talent scout at Decca Records, wrote, “We don’t like your boys’ sound. Groups are out; four-piece groups with guitars, particularly, are finished.”
The Heaths use Rowe’s confident dismissal to illustrate overconfidence. People think they know more than they do about how the future will unfold.
Andy Grove’s colleagues at Intel had dire predictions of what would happen if Intel stopped making memory chips. We will lose the seedbed of our R&D. Our sales force can’t succeed without a full line of products. History proves that they were wrong: Intel’s R&D and sales stayed strong. But what’s interesting is that, at the time they made these proclamations, they didn’t feel uncertain. They weren’t hedging their remarks by saying, “It’s possible that …” or “I just worry that this could happen someday.…” They knew they were right. They just knew it.
A study showed that when doctors reckoned themselves “completely certain” about a diagnosis, they were wrong 40% of the time. When a group of students made estimates that they believed had only a 1% chance of being wrong, they were actually wrong 27% of the time.
We have too much confidence in our own predictions. When we make guesses about the future, we shine our spotlights on information that’s close at hand, and then we draw conclusions from that information. Imagine the head of a travel agency in 1992: My travel agency is the market leader in Phoenix, and we have the best customer relationships. This area is growing so rapidly, we could easily double in size over the next ten years. Let’s get ahead of the curve and build those additional branches.
The problem is that we don’t know what we don’t know. Whoops, the Internet. So much for my travel agency.
The future has an uncanny ability to surprise. We can’t shine a spotlight on areas when we don’t know they exist.
The Heaths connect four recurring decision problems to stages of a choice:
- When identifying options, narrow framing can hide alternatives.
- When analyzing options, confirmation bias can skew the evidence gathered.
- When choosing, short-term emotion can outweigh longer-term considerations.
- When committing to a choice, overconfidence can obscure how differently the future might unfold.
A pros-and-cons list needs additional checks if it is to address these problems, including a deliberate search for alternatives and evidence that challenges a preferred forecast.
When to use it
When making a business forecast about market trends, overconfidence can lead to overinvestment in a single strategy—mitigate by generating multiple scenarios.
In personal finance, overconfidence about investment returns can cause risky asset allocation—use base rates and diverse perspectives to calibrate.
When hiring, an overconfident belief that a candidate is perfect can overlook red flags—use structured interviews and check references.
In project planning, overconfidence in timelines (planning fallacy) leads to delays—use reference class forecasting to ground estimates.
FROM THEORY TO EVERYDAY LIFE
In practice
Decca Records rejects the Beatles
In 1962, Decca Records passed on signing the Beatles after an audition, with talent scout Dick Rowe stating "We don't like your boys' sound. Groups are out; four-piece groups with guitars, particularly, are finished." This decision was overconfident, as the Beatles went on to become one of the most successful bands in history.
Western Union rejects the telephone
William Orton, president of Western Union, rejected Alexander Graham Bell's telephone patent in 1876, asking "What use could this company make of an electrical toy?" This demonstrated overconfidence in their ability to predict the future value of the invention.
Doctors' overconfidence in diagnoses
The Heaths cite a study in which doctors’ diagnoses described as "completely certain" were wrong 40% of the time. The reported figure illustrates a gap between confidence and accuracy in that sample, rather than an error rate for all doctors or diagnoses.
Travel agency expansion in 1992
A hypothetical travel agency head in 1992 assumed the future would mirror past growth, planning to double in size, only to be blindsided by the rise of the internet, which disrupted the industry.
A MOMENT TO REFLECT
Put it to work.
Think of a time when you were completely certain about a future outcome but turned out to be wrong. What information were you ignoring?
How can you build a habit of actively considering what you might not know before making a prediction?
What specific steps could you take to reduce overconfidence in your own decisions, such as seeking disconfirming evidence?
CONTINUE THE CONVERSATION
Source texts
- Decisive How to Make Better Choices in Life and Work (Chip Heath)