Evidence Based Orthopaedics: Diagnostic Studies addresses the key principles of evaluating the strength of diagnostic studies to provide the concepts necessary for efficient reading of diagnostic studies. This module reviews the use of precision and accuracy, specificity (rule-in) and sensitivity (rule out), likelihood ratios, and predictive values by applying these concepts to case studies. These cases demonstrate how to calculate and apply these concepts to the interpretation of both pre-test and post-test diagnostic test performance.