Availability Bias

What is it?

The availability heuristic, identified by Kahneman and Tversky, is the tendency to judge the frequency or probability of an event by how easily examples come to mind. Events that are recent, dramatic, or emotionally charged are more "available" to memory and thus seem more common than they actually are. This explains why people overestimate risks of plane crashes (dramatic news coverage) while underestimating risks of car accidents (mundane and unreported). Media coverage heavily distorts our risk perception—we fear terrorism more than heart disease despite vast differences in actual risk. In business, recent failures loom large in memory while past successes fade, leading to excessive risk aversion. Conversely, a recent success can breed overconfidence. The bias affects medical diagnoses (doctors over-diagnose conditions they've recently seen), investment decisions (recent market events dominate thinking), and policy-making (responses driven by recent crises). To counteract availability bias, seek statistical data rather than relying on memorable examples, and deliberately consider base rates and historical patterns rather than recent events alone.