Original ArticlesRating Scales, Scales of Measurement, Issues of Reliability Resolving Some Critical Issues for Clinicians and ResearchersCicchetti, Domenic PhD*†; Bronen, Richard MD‡; Spencer, Susan MD‡; Haut, Sheryl MD§; Berg, Anne PhD∥; Oliver, Patricia PhD¶; Tyrer, Peter MD¶Author Information *Department of Biometry, Yale University School of Medicine, New Haven, Connecticut; †School of Public Mental Health, Imperial College of Science, Technology, and Medicine, London, United Kingdom; ‡Department of Neurology, Yale University School of Medicine; §Departments of Neurology and Pediatrics, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York; ∥Biological Sciences, Northern Illinois University, DeKalb, Illinois; and ¶Department of Psychiatry, Imperial College of Science, Technology, and Medicine, London, United Kingdom. Send reprint requests to Domenic Cicchetti, PhD, Yale Home Office, 94 Linsley Lake Road, North Branford, CT 06471. The Journal of Nervous and Mental Disease: August 2006 - Volume 194 - Issue 8 - p 557-564 doi: 10.1097/01.nmd.0000230392.83607.c5 Buy Metrics Abstract We focus upon several broad issues that are of concern to clinicians and clinical researchers in the areas of biobehavioral and biomedical research, including, but not limited to, the fields of psychiatry, psychology, neuropsychology, and neurology. These issues are the critical reassessment of S. S. Stevens’ quadripartite conceptualization of scales of measurement; the application of criteria to determine the clinical significance of reliability estimates; the detection of subsets of reliable and unreliable raters, when the overall level is of little clinical import; and finally, the application of Kappa statistics when multiple raters evaluate a single case. © 2006 Lippincott Williams & Wilkins, Inc.