Public Health and the Eye

The reliability of clinical methods is often taken for granted. There is considerable evidence, however, that variability of clinical measurements, interpretations, and judgements are greater than commonly thought. Inconsistency of clinical methods has profound and widespread implications in clinical practice. The inferential capacity of measurements depends on accuracy and reproducibility. Appropriate medical decisions cannot be reached without accurate and reliable data. This review will examine the conceptual relationship of reliability, accuracy, and validity. The role of observer reliability in ophthalmic test measurements and interpretations will be addressed in the context of three case reports. ( Surv Ophthalmol 47 :375–386, 2002. © 2002 by Elsevier Science Inc. All rights reserved.)