NPV {evidence}

computes the Negative Predictive Value.

Description

The negative predictive value (NPV) of a diagnostic test is the probability that someone with a negative diagnostic test for a condition does not have the condition. The NPV can easily be calculated from the prevalence, the sensitivity, and the specificity, but this function automates the procedure.

Usage

NPV(sens, spec, prev)

Arguments

sens

the sensitivity of the test

spec

the specificity of the test

prev

the prevalence of the disease

Value

the negative predictive value

Author(s)

Robert van Hulst

References

van Hulst, R. 2018. Evaluating Scientific Evidence. ms.

See Also

PPV

Examples

NPV(0.9, 0.8, 0.003)