Toward the behavioral assessment of biological aging in the laboratory mouse: concepts, terminology, and objectives.

The thesis is presented that much of the controversy and confusion concerning the measurement of biological aging stems from the lack of agreement on clearly defined objectives, constructs, and methods to validate measures. To alleviate some of the confusion, basic terminology borrowed from psychometrics is offered to provide a conceptual framework within which such issues can be discussed. This psychometric nomenclature is subsequently applied to the development and evaluation of a test battery designed to assess biological aging in laboratory mice at a behavioral level of analysis. Reference is made to the assessment of reliability, content validity, construct validity, and predictive validity of tests of biological aging.