Base Rate Neglect
🇳🇴Neglisjering av basisrateDefinition
Base rate neglect is the tendency to ignore general statistical information (base rates) in favor of specific, often vivid information, leading to systematic errors in probability judgments.
Real-world example
In hiring, interviewers may overestimate a candidate's likelihood of success based on a strong personal impression while ignoring base rates for how often similar candidates actually perform well. In medical diagnosis, clinicians may overestimate rare diseases based on symptom descriptions while overlooking their low prevalence.
Supplementary perspective
Base rate neglect is closely linked to the representativeness heuristic: people judge likelihood based on how typical something seems rather than how common it actually is. The bias is amplified when information is presented as stories rather than statistics.
Practical advice
Recognize
- —Notice whether single cases outweigh statistical information in your reasoning.
Counteract
- —Always start with the base rate before incorporating new evidence.
- —Think in numbers and frequencies rather than narratives.
Ethical use
- —Present statistics in an accessible way alongside concrete examples.
- —Avoid overemphasizing unrepresentative anecdotes.