Using linked administrative data to determine the prevalence of intellectual disability in adult prison in New South Wales, Australia

Abstract

Background Studies of the representation of people with intellectual disability (ID) in custody report widely inconsistent findings that reflect variation in how ID is defined and the methods employed for identification. Using linked administrative data may be of utility in studies of the representation of people with ID in custody. However, this approach requires an understanding of the purpose of and factors influencing identification in disparate administrative datasets. Methods This study uses linked administrative data encompassing disability, health and corrections data for the year 2014 to estimate the prevalence of ID in adult custody and explore how ID representation within administrative data impacts prevalence estimates and what patterns of identification reveal about support service access for this group. Results This study finds that 4.3% of the New South Wales adult custody population had an identified ID. Prisoners with ID were younger, more likely to have had a previous custodial episode and more likely to be Indigenous than the general prison population. Identification of ID across linked administrative datasets is uneven, which, if used in isolation, would result in variation in prevalence estimates according to source data. Conclusions The utilisation of linkage data from a broad range of health and support services including custody offers a comprehensive identification methodology. Inconsistency in the identification of ID across datasets indicates a potential disjuncture between prisoners with ID and support services, which may have relevance for efforts to reduce reincarceration of those in this population.

Predictors and outcomes of recognition of intellectual disability for adults during hospital admissions: A retrospective data linkage study in NSW, Australia

“…This difference was particularly stark for individuals in custody, where fewer than 10% of episodes that occurred when the individual was in custody recognised intellectual disability. Our findings are particularly concerning given the over-representation of individuals with intellectual disability in custody, and their need for extra support (not less) to prevent recidivism [ 21 ]. Overall, the results suggest a blindness to the presence of intellectual disability in such individuals, risking lack of activation of supports in areas that are critical to their future trajectory.…”

“…Such a flag assists identification of the disability, and triggers the need to ask about and document the adjustments required by the person during their contact with the health service. However, research suggests that intellectual disability is not consistently recognised during receipt of health and human services, and that recognition varies according to the sector with which the person has contact, creating an impediment to the uniform application of reasonable adjustments [ 11 , 18 – 21 ]. Though previous research has examined factors that affect the recognition of intellectual disability in children [ 20 ], the factors that determine recognition of intellectual disability for adults during inpatient episodes (and therefore provision of reasonable adjustments) and the impact of this identification on the episode of care have not been identified.…”

Crimes and sentences in individuals with intellectual disability in a forensic psychiatric context: a register-based study

“…A longitudinal study from Australia showed that offenders with ID were more likely to receive CSM or to be discharged according to insanity defence legislation than the non-disabled sample (Cockram, 2005 ). Nevertheless, the prevalence of ID in prison systems has been estimated at 2–10% (Hellenbach et al ., 2017 ; Martí-Agustí et al ., 2019 ; Trofimovs et al ., 2021 ). What characterises offenders with ID who are sentenced to prison in comparison to those who are diverted to other sanctions pre- or post-trial is largely unknown.…”

Intellectual/developmental disabilities among people incarcerated in federal correctional facilities in Ontario, Canada: Examining prevalence, health and correctional characteristics

“…Australian study that found a prevalence of 4.3% among an adult custody population using linked administrative data (disability, health, and corrections) (Trofimovs et al, 2021) and a UK study that found that 11% of the sample of young adult males in prison had borderline intellectual disability (Herrington, 2009).…”