Fundamental measures of diagnostic examination performance: usefulness for clinical decision making and research.

Measures of diagnostic accuracy, such as sensitivity, specificity, predictive values, and receiver operating characteristic curves, can often seem like abstract mathematic concepts that have a minimal relationship with clinical decision making or clinical research. The purpose of this article is to provide definitions and examples of these concepts that illustrate their usefulness in specific clinical decision-making tasks. In particular, nine principles are provided to guide the use of these concepts in daily radiology practice, in interpreting clinical literature, and in designing clinical research studies. An understanding of these principles and of the measures of diagnostic accuracy to which they apply is vital to the appropriate evaluation and use of diagnostic imaging examinations.