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.

Keywords:

• Court judgements
• fitness to stand trial
• forensic evaluation
• intellectually disabled defendants
• IQ threshold
• New Zealand court system
• Presser criteria

Ethical standards

Declaration of conflicts of interest

Joseph A. E. Sakdalan has declared no conflicts of interest.

Khan Buchwald has declared no conflicts of interest.

Sabine Visser has declared no conflicts of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the Health and Disability Ethics Committee, New Zealand and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was not obtained from individual participants because it was an archival study, and aggregate and de-identified data were used. This research is out-of-scope and did not require a full ethics application, as determined by the Health and Disability Ethics Committee, New Zealand, considering this is an audit-related activity instead of an intervention study.