age-equivalent score

n. A raw score that corresponds to the chronological age of the norm group who obtained a similar score. Age-equivalent scores should only be used for relative comparisons of performance on a given assessment measure, not for diagnostic or placement purposes. Because most abilities and skills are acquired more rapidly during the early years than during later years of development, age-equivalent scores do not have equal intervals. For example, the difference in language/vocabulary of a 4- and a 7-year-old is considerably different from the difference in language/vocabulary between a 24- and a 27-year-old despite the fact that both are characterized by a 3-year chronological age difference. Because age- equivalent scores lack the properties of ratio or interval scales, they cannot be mathematically manipulated. - BJM