The innate tilt toward underweighting risk and overweighting favorable outcomes — because believing good news simply feels better.
"What a man wishes, he will also believe."
A person wants a particular result — a deal to close, a diagnosis to be minor, a venture to succeed.
Unfavorable evidence is quietly underweighted while favorable evidence is readily accepted.
A decision gets made on hoped-for odds rather than actual odds — and the gap surfaces later, at cost.
Ahead of the 1986 Space Shuttle Challenger launch, engineers raised warnings about O-ring performance in cold temperatures; schedule pressure and a preference for a successful launch led decision-makers to discount those warnings, a failure later analyzed by physicist Richard Feynman and sociologist Diane Vaughan as a case of "normalized" risk.
U.S. Bureau of Labor Statistics data consistently show that a substantial share of new businesses close within their first several years, yet founders routinely enter with confidence levels far exceeding these base rates — a persistent, well-documented gap between wished-for and actual odds.
In August 1914, leaders and soldiers on multiple sides of what became World War I widely expected a short, decisive conflict — a documented mood of confident optimism that preceded a war that instead ground on for more than four years.
Build explicit base-rate checks into every optimistic forecast before acting on it.
Run a pre-mortem: assume the plan failed, and write down the most plausible reasons why.
Deliberately separate what you want to happen from what the evidence says is likely to happen.
Invite the most credible skeptical voice available into the room before committing.
Track past forecasts against actual outcomes to calibrate how optimistic you tend to run.
Wishing distorts assessment so reliably that any forecast unchecked by base rates should be treated as a wish wearing the costume of a prediction.