Estimation of premorbid IQ is an integral part of many
neuropsychological assessments, but there has been little research on the efficacy of clinical judgement versus actuarial methods in this area, and only one study has examined the methods used by clinicians to estimate IQ. In this thesis experienced and novice neuropsychologists' estimation of intellectual function were compared to objective IQ data and a number of actuarial methods. A survey of methods for estimating premorbid IQ used by experienced Australian, North American and British neuropsychologists and novice Australian neuropsychologists was also conducted.