ABSTRACT
Everything that exists, exists in some quantity and can therefore be measured. Age scales have been supplanted in most countries, and certainly for adult testing, by point scales, although for the sake of convenience, point scales are usually interpreted in terms of intelligence quotient (IQ) – in spite of the fact that these scores have nothing to do with quotients of any kind. This chapter discusses the age scales, and in particular the Binet-Simon scale, point scales, particularly the Wechsler scales, and considers the Rasch-type scales. It also discusses some general problems of measurement which apply to all these scales. By definition the mean IQ of a given group or population must be 100, and scores above 100 indicate high intelligence, scores below 100 low intelligence. Nearly all modern IQ tests are point scales, translated into IQ equivalents.
