 This article emphasizes the importance of understanding sensitivity, specificity, and predictive values in screening tests and provides clarification on their definitions and misconceptions. It suggests that sensitivity and specificity should be used in relation to a reference standard while predictive values are more appropriate for actual screening contexts. The article also argues that adjusting the sensitivity and specificity of screening tests can be beneficial in certain situations and encourages researchers to provide information about all four metrics for effective interpretation by consumers of health research. This article was authored by Robert Trevethen.