Health psychology/Cognitive biases · Clinical reasoninglow yield

Gambler’s fallacy

What it means

Believing that a run of one outcome makes the opposite more "due", treating independent events as if they were linked.

Worked example

"I’ve admitted four PEs today, so this breathless patient surely won’t have one."

In the exam

Having diagnosed several patients with the same condition in one shift, a doctor reasons that the next similar patient is unlikely to have it "after so many already".

What settles it

Gambler’s fallacy treats independent presentations as if a streak changes the odds. Base-rate neglect ignores the underlying prevalence; the gambler’s fallacy specifically misapplies the idea of being "due".

Classically confused with

Base-rate neglect

Source: Croskerry