nnd {ClinSigMeasures}

Number Needed to Diagnose Calculation From a 2x2 Table

Description

Calculates the Number Needed to Diagnose for data from a 2x2 table

Usage

nnd(Cell1, Cell2, Cell3, Cell4)

Arguments

Cell1

Value for cases with a positive test

Cell2

Value for controls with a positive test

Cell3

Value for cases with a negative test

Cell4

Value for controls with a negative test

Value

Number Needed to Diagnose

Author(s)

Mike Malek-Ahmadi

References

1. Larner AJ. Number Needed to Diagnose, Predict, or Misdiagnose: Useful Metrics for Non-Canonical Signs of Cognitive Status? Dement Geriatr Cogn Disord Extra 2018;8:321–327

Examples

#From Shaikh (2011), page 3, 2x2 table for "Diagnostic Test Evaluation"
#NND is the inverse of the Youden Index (1 / Youden Index)

nnd(105, 171, 15, 87)