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False Negative Rate

False negative rate is the probability of a negative test when the condition is true, equal to 1 minus sensitivity.

Definition

False negative rate is P(test negative given condition true). It equals 1 minus sensitivity.

Why it matters

False negatives weaken the evidence of a negative result. In Bayes terms, high false negative rate reduces how much a negative test should shift your belief.

How it connects

• Lower false negative rate increases the value of a negative result.

• It contributes to likelihood ratio calculations used in Bayes updates.

Common pitfalls

Assuming a negative test clears the condition: The posterior still depends on base rate.