A note on Youden's J and its cost ratio.

ABSTRACT:

Background

The Youden index, the sum of sensitivity and specificity minus one, is an index used for setting optimal thresholds on medical tests.

Discussion

When using this index, one implicitly uses decision theory with a ratio of misclassification costs which is equal to one minus the prevalence proportion of the disease. It is doubtful whether this cost ratio truly represents the decision maker's preferences. Moreover, in populations with a different prevalence, a selected threshold is optimal with reference to a different cost ratio.

Summary

The Youden index is not a truly optimal decision rule for setting thresholds because its cost ratio varies with prevalence. Researchers should look into their cost ratio and employ it in a decision theoretic framework to obtain

SUBMITTER: Smits N 

PROVIDER: S-EPMC2959030 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature