functional age
an individual’s age as determined by measures of functional capability indexed by age-normed standards. Functional age is distinct from chronological age and represents a combination of physiological, psychological, and social age. The functional age of a child is measured in terms of the developmental level he or she has reached. It may be compared with his or her chronological age as a means of gauging the existence and extent of any impairment or developmental problem. In older adults, it is calculated by measuring a range of variables that correlate closely with chronological age, such as eyesight, hearing, mobility, cardiopulmonary function, concentration, and memory. Following the passing of the Age Discrimination in Employment Act, functional age, rather than chronological age, has been made a criterion for employment in some jobs.