Evidence of significant impairment in cognitive functioning has always been one of the main criteria of a learning disability (Pulsifer, 1996) and intellectual assessment is, therefore, one of the tasks of clinical psychologists working within learning disability services. Such assessments are commonly used to help establish of an individual’s cognitive strengths and weaknesses, support needs and more specifically, to help determine if an individual falls within the remit of learning disability services (McKenzie & Murray, 2002, Evers & Hill, 1999). Intellectual assessments also have important implications in terms of mental health legislation, accessing benefits and services and informing legal decision-making processes (British Psychological Society, 2001, McKay, 1991). It is, therefore, crucial that the assessments are valid, reliable and used only by appropriately trained and qualified professionals. In Britain, it is emphasised that assessing an individual’s intellectual functioning requires an individually administered, standardised psychometric assessment which is reliable and valid (British Psychological Society, 2001), while in America professional mandates, such as the Standards for Educational and Psychological Testing (AERA,APA & NCME, 1985) highlight the need for high standards of administrative accuracy from psychologists. The Wechsler Adult Intelligence Scales - Third Edition (Wechsler, 1998) are commonly used in intellectual and neuropsychological assessment and are considered to be valid, reliable and well-standardised (Groth-Marnat et al, 2000). The Wechsler Scales have a long history and have undergone a number of revisions with the most recent being in 1997 with the development of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). The purpose of these revisions was to insure that the standardisation sample was representative of current demographics and performance, to update the subtests, incorporate new subtests, and refine the instructions and test materials. Each revision has been well researched and validated (Groth Marnat et al, 2000).
|Publication status||Published - Nov 2004|