age scale

n. Age scales group measurement items according to the age at which the average test taker can correctly complete the item (as opposed to simply ordering items according to increasing difficulty). The age scale concept is based on age differentiation theory, which states that children of increasing age have greater intellectual capabilities. As such, while age scales are effective measures for children whose abilities vary widely from year to year, they are generally ineffective for use on adult populations, who show little variability in intellectual capabilities as a function of age. Popularized by Binet in the development of the 1908 Binet-Simon intelligence scale, age scales are now commonly used in educational and clinical assessments.   -BJM