Assessing Intellectual Disability in Children: Are IQ Measures

Anumber of critical issues concerning the assessment of children with intellectualdisabilities, including definitional problems, psychometric factors,and practical difficulties, are raised in this article. It is suggested thatschool counsellors and psychologists should consider these issues when assessing children with probable or known intellectual disabili-ties, particularly when using IQ tests. The use of adaptive scales as an additional means of defining and measuring intellectual disability is also examined. Although no ideal means of formally assessing chil-dren with intellectual disabilities is put forward, a range of concerns is explored and some suggestions for appropriate additions and caveats to present practice are proposed. Over one hundred years ago, the first test of intelligence was developed by Binet in order to identify children having difficulties learning in regular education. Binet’s original measure of intelligence was constructed relative to age-typical cognitive functioning, and this theme of developmental normality remains implicit in our def-initions and measures of intelligence and intellectual disability in the 21st century. Over time, increasing sophistication in psychometric principles and applications has occurred, resulting in the reliable measurement of intelligence (commonly known as IQ) across most age groups and levels of cognitive ability. However, questions still remain about the validity of intelligence; firstly, as a psy-chological construct (MacMillan, Gresham, & Siperstein, 1993) and, secondly, in terms of its predictive capacity (Neisworth & Bagnato, 1992). Further, differing definitions and models of intelligence exist and cognitive processes are more com-plex than quantitative scores derived using standardised instruments (Howe, 1997