IQ thresholds and influence of the assessor’s professional discipline on fitness to stand trial assessment outcomes in Aotearoa New Zealand

Abstract

There is considerable variability in fitness to stand trial (FST) findings between assessors, which may potentially influence the courts’ decisions for defendants with intellectual disability (ID). This study aims to determine the influence of the defendant’s intelligence quotient (IQ) score and the assessor’s professional discipline on FST findings and court outcomes for ID defendants in Aotearoa New Zealand. This study included 146 defendants with ID who were assessed between 2005 and 2015. Study findings revealed that psychologists find defendants unfit to stand trial at a higher IQ score than psychiatrists. Notwithstanding, there was a general agreement between the professions regarding the defendant’s fitness to stand trial. Furthermore, the assessor’s discipline did not appear to unduly influence the court’s decision on fitness to stand trial. NZ court cases are discussed to highlight the issues with mild to moderate ID defendants previously found fit to stand trial.