In this study we examined further the reliability, validity, and efficacy of the 3CL in distinguishing among groups of normal individuals, those with cognitive complaints, amnestic and non-amnestic MCI cases, and early-stage demented individuals.Scale validation study.Alzheimer's Disease Research CenterOne hundred and twenty-five individuals who completed extensive evaluations as part of a longitudinal study of cognitive change.Scale reliabilities were found to be well within guidelines to support their use in the clinical assessment of change in global and specific cognitive domains. The factor structure of the 3CL was found to be highly similar to that originally reported. Validation support was obtained from correlational analyses that showed significant scale relationships with neuroco...