The article by Robert Trevethan discusses the importance of understanding sensitivity, specificity, and predictive values in the context of screening tests. It emphasizes the need to avoid misconceptions about these metrics and provides a foundation for their interpretation. The author clarifies the definitions of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), highlighting how they are often misunderstood and misused. Sensitivity and specificity are typically used to describe a screening test's attributes relative to a reference standard, while PPV and NPV are more informative in actual screening contexts. High sensitivity and specificity can be useful if they are extremely high, but they should not be relied upon for individual decisions. The article also discusses the trade-offs between sensitivity and specificity, and the pliability of these metrics. It stresses the importance of researchers providing complete information about screening tests, including all four metrics and their derivation, to ensure that consumers can interpret the results effectively. The article concludes by emphasizing the need for a clear understanding of these metrics to maximize the benefit to clients and the healthcare system.The article by Robert Trevethan discusses the importance of understanding sensitivity, specificity, and predictive values in the context of screening tests. It emphasizes the need to avoid misconceptions about these metrics and provides a foundation for their interpretation. The author clarifies the definitions of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), highlighting how they are often misunderstood and misused. Sensitivity and specificity are typically used to describe a screening test's attributes relative to a reference standard, while PPV and NPV are more informative in actual screening contexts. High sensitivity and specificity can be useful if they are extremely high, but they should not be relied upon for individual decisions. The article also discusses the trade-offs between sensitivity and specificity, and the pliability of these metrics. It stresses the importance of researchers providing complete information about screening tests, including all four metrics and their derivation, to ensure that consumers can interpret the results effectively. The article concludes by emphasizing the need for a clear understanding of these metrics to maximize the benefit to clients and the healthcare system.