NPV function

computes the Negative Predictive Value.

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.

NPV(sens, spec, prev)

Arguments

• sens: the sensitivity of the test
• spec: the specificity of the test
• prev: the prevalence of the disease

Returns

the negative predictive value

References

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

Author(s)

Robert van Hulst

See Also

PPV

Examples

NPV(0.9, 0.8, 0.003)