Intertester reliability assesses what?

• A. Consistency of measurements by the same tester
• B. Consistency of measurements between different testers
• C. Predictive validity
• D. Internal consistency of a test

Answer: (B)

Intertester reliability looks at whether different testers obtain similar results when assessing the same patient or performing the same test. This matters because if the outcome changes depending on who administers the test, the results may reflect tester effect rather than the patient’s actual status. A high level of agreement between testers means the measurement is dependable across examiners, which is essential for consistency in clinical decision-making. This differs from intra-tester reliability, which is about the same tester being consistent across time, and from predictive validity (whether the test predicts future outcomes) or internal consistency (how well items on a test measure the same construct). In practice, intertester reliability is quantified with statistics like the intraclass correlation coefficient for continuous data or Cohen’s kappa for categorical judgments.