What is Negative Predictive Value (NPV)

The clinical utility of a measure involves its ability to support a wide range of decisions that enhance its pragmatism and use. Although several statistics are part of this feature, one centerpiece of this concept is the ability of an instrument to provide cutoff scores that can accurately discriminate between groups that consist of patients and non-patients. This latter aspect leads to such concepts as sensitivity, specificity, positive and negative predictive values and likelihood ratios, accuracy, and receiver operating characteristic curves. This chapter addresses these topics from two perspectives. First, because these features of clinical utility are encompassed as a subfield of statistical decision theory, the authors provide a historical review that links null hypothesis significance testing (NHST), signal detection theory (SDT), and psychological testing. Second, a real-data approach is used to demonstrate these concepts. Additionally, a free software program was developed to present these concepts.