Table 1: Offenders - Estimates of Prevalence

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Offenders with an Intellectual Disability	Source (see Select Bibliography for full citation)
12-13% of prison population have an intellectual disability.	NSW: Hayes and McIlwain (1988) at 47.
5% of prisoners serving sentences longer that 12 months have an IQ less than 70.	NSW: J Gordon (1980) Research Officer, New South Wales Department of Corrective Services, personal communication with authors: Hayes and Craddock (1992) at 33.
Of juvenile offenders, 2.1% had an IQ below 70, and 11.3% had and IQ of 70-80. Estimated 7.7% of young offenders on control orders have an intellectual disability.	NSW: New South Wales - Department of Family and Community Services (1989) at 22 (Appendix E).
2-20% of prisoners have an intellectual disability.	NSW: 1983 informal survey cited in New South Wales - Inter-departmental Committee on Intellectually Handicapped Adult Offenders in New South Wales Australia (1985) at 25.
14.2% of the sample of persons appearing before Local Courts were in the mildly intellectually disabled range of cognitive ability with a further 8.8% in the borderline intellectual disability category.	NSW: New South Wales Law Reform Commission RR4 (1993).
36% of the sample of persons appearing before Local Courts were in the mildly intellectually disabled range of cognitive ability with a further 20.9% in the borderline intellectual disability category.	NSW: New South Wales Law Reform Commission RR5 (1996).
3-4% of prison population have an IQ below 69.	Victoria: Bodna (1987) at 21.
At least 2-3% of juvenile offenders surveyed between 1984 and 1986 had an IQ below 69.	Victoria: Bodna (1987) at 18 and 19.
At least 1.3% of prison population has an intellectual disability.	WA: Fitzgerald and Downs-Stoney (1987).
1.17% of prison population is intellectually disabled.	WA: Jones and Coombes (1990) at 27.
0.5% of offenders coming before the lower and higher courts have an intellectual disability.	WA: Jones and Coombes(1990) at 4.
50-80 clients of intellectual disability services charged each year with a criminal offence.	WA: G Jones "Doing something positive: Developments in Western Australia" in Challinger (ed) (1987) 129 at 131.
A range of 2.6-24.3% of prisoners across various States have an intellectual disability, with a national average of 9.5% with an IQ below 70, and 1.6% with an IQ belwo 55.	USA: Brown and Courtless (1971) at 29-31.
On average 2% or 6.2%, depending upon the testing method utilised, of prisoners across various States have an intellectual disability.	USA: Denkowski and Denkowski (19850 at 59-62.
40% of prison population have an IQ below 86.	USA: R March, C Friel and V Eissler "The adult MR in the criminal justice system" (1975) cited in Russell and Bryant (1987) at 54.
13% of male and 17% of female admissions to a juvenile offender service in Texas had an IQ below 70.	USA: D Kirkpatrick and J Haskins The Mentally Retarded Youthful Offender: A Preliminary Statistical Summary (1971) cited in Hayes and Craddock (1992) at 38.
9% of suspects at police station had an IQ below 70 and a further 42% had an IQ scores between 70 and 79.	UK: Gudjonsson, Clare, Rutter and Pearse (1993).
10% of prison population has an intellectual disability.	Denmark: B Svendsen and J Werner "Offenders within ordinary services for the mentally retarded in Denmark" cited in Hayes and Craddock (1992) at 32.
3.4-30% of juvenile offenders have an intellectual disability as compared with 1.86% of children with an intellectual disability receiving special education (from a review of various surveys).	D Murphy "The prevalence of handicapped conditions among juvenile delinquents" (1986) cited in Hayes and Craddock (1992) at 39.

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Table 2: Offenders - Types of Crime

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Offenders with an Intellectual Disability	Source (see Select Bibliography for full citation)
Incidence of sex offending similar for prisoners with an intellectual deficit (3.7%) and the non-intellectually disabled (4%).	NSW: Hayes and McIlwain (1988) at 36.
13% of registered clients with the Office of Intellectual Disability (Community Services Department) had been involved with the criminal justice system as offenders, the most common offences being theft and indecent or sexual assault.	Victoria: Bodna (1987) at 13-15.
Of the 77% of Disability Service (intellectually disabled) clients surveyed: 1.7% had been convicted of a criminal offence, 33% of these offences were considered of a type dangerous to public safety.	Victoria: Community Services Victoria, Office of Intellectual Disability Services, Submission to the Victorian Parliament Social Development Committee's Inquiry into Mental Distrubance and Community Safety (Fourth Report, 1992) at 121.
66.7% of intellectually disabled and 46.2% of borderline offenders incarcerated for offences against the person as compared with 4.5% of the non-intellectually disabled prison population.50% of intellectually disabled and 30.8% of borderline offenders incarcerated for sex offences as compared with 15.4% of the non-intellectually disabled prison population.	WA: Jones and Coombes (1990) at 21-22.
35.4% of sample group convicted of property offences as compared to 1.8% of general prison population. 11.8% of sample group convicted of sex offences and traffic offences, as compared with 10.4% and 15.9% respectively in the general prison population. 5.9% of sample group convicted for theft as compared with 24.6% in general prison population.	WA: Fitzgerald and Downs-Stoney (1987) at 9.
63.1% of intellectually disables offenders in Kentucky prisons had committed crimes against the person and 36.9% against property.	USA: State of Kentucky, Legislative Research Commission "Mentally retarded offenders in adult and juvenile correctional institutions" (1975) cited in Sanatamour and West (1977) at 8.
No significant relationship between intellectual disability and type of offence committed.	USA: W McConochie "Juvenile delinquents: Relationships between WISC score, offences, race, chronological age, and residence"(1970) cited in Santamour and West (19770 at 8.
50% of intellectually disabled prisoners convicted of sex offences.	USA: G Gross Activities of the Deveolopmental Disabilities Adult Offenders project (1985) cited in W Glaser "A comparison of intellectually disabled and non-disabled sex offenders" in Freckelton, Greig and McMahon (eds) (1991) 243 at 247.
10-15% of sex offenders are intellectually impaired.	USA: W Murphy, E Coleman and M Haynes "Treatment and evaluation issues with the mentally retarded sex offender" (1983) cited in W Glaser " A comparison of intellectually disabled and non-intellectually disabled sex offenders" in Freckelton,, Greig and McMahon (eds) (1991) 243 at 243.
Nearly 40% of offender found to be intellectually disabled were sentenced for criminal homicide (not necessarily murder). Intellectually disabled prisoners found to have committed higher ratio of homicide and other violent crimes, and had more convictions and a longer history of imprisonment, than non-disabled prisoners.	USA: R Allen "Legal norms and practices affecting the mentally deficient" (1968) cited in S Hayes "Prosecutorial descretion and mentally abnormal offenders" in Potas (ed) Prosecutorial Discretion (1984) 191 at 194.
50% of victims of sex offences with an intellectual disability are women, compared to 89% of victims of non-intellectually disabled sex offenders.	USA: D Griffiths, D Hingsburger and R Christian "Treating developmentally handicapped sexual offenders: The York Behavioural Management Services Treatment Program" (1985) cited in Hayes "Sex offenders" (1991) at 2.
Percentage of intellectually disabled offenders dealt with for sexual offences was six times higher than the percentage for all offenders.	UK: G Simon "A manual of practice" (1980) cited in M Little "Sport and recreation: Help for intellectually disabled offenders" in Challinger (ed) (1987) 113 at 117.
15% of adolescent and 10% of adult arsonists were intellectually disabled.	Canada: J Bradford and J Dimock "A comparitive study of adolescents and adults who wilfully set fires" (1986) cited in Hayes and Craddock (1992) at 44.
3-4% of exhibitionists and paedophiles are intellectually disabled.	Canada: J Mohr, R Turner and M Jerry Paedophilia and Exhibitionism, Toronto (1964) cited in W Glaser " A comparison of intellectually disabled and non-disabled sex offenders" in Freckelton, Greig and McMahon (eds) (1991) 243 at 247.
Higher and increasing incidence of sex offenders among intellectually disabled persons.	Denmark: L Lund "Mentally retarded criminal offenders in Denmark" (1990) cited in W Glaser "A comparison of intellectually disabled and non-disabled sex offenders" in Freckelton, Greig and McMahon (eds) (1991) 243 at 247.

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Table 3: Victims - Estimated of Prevalence and types of crimes

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Victims with an Intellectual Disability	Source (see Select Bibliography for full citation)
6.4% of adults referred to Sexual Assault Services of the NSW Department of Health had an intellectual disability.	NSW: New South Wales Department of Health (1990) Adult Sexual Assault Data Collection, January-June 1989 cited in New South Wales - Women's Co-ordination Unit (1990) at 11.
Of intellectually disabled victims, 70.34% were sexually assaulted, 5.51% assaulted, 2.75% murdered, 1.37% theft victims and the remaining 20% victims of unspecified crimes.	Victoria: Johnson, Andrew and Topp (1988) at Appendix 4.
Victimisation rated of people with an intellectual disability: Offences against the person (assault, sexual assault, robbery, auto theft, other theft): 25.3% of people with an intellectual disability are likely to be a victim compared to 10.5% of the general population; Household offences (break and enter, household property theft): 13.3% of people with an intellectual disability are likely to be a victim compared to 9.8% of the general population.	SA: Wilson (1990) at 7.
Intellectually disabled individuals are more likely than non-disabled adults to be the victims of personal and household offences.	SA: Wilson and Brewer (1992) at 115.
75% of intellectually disabled people studied had survived at least one sexual assault, 99% of which had been committed by a person known to the victim.	USA: Seattle Rape Releif Project study cited in R Luckasson "People with mental retardation as victims of crime" in Conley, Luckasson and Bouthilet (eds) (1992) 209 at 210.
25% of 87 adolescent females with an intellectual disability had been sexually abused.	USA: A Chamberlain, J Rauh, A Passer, M McGrath and R Burket "Issues in fertility control for mentally retarded female adolescents: 1. Sexual activity, sexual abuse and contraception" (1984) cited in Tharinger, Burrows Horton and Millea (1990) at 304.
1 in 30 cases of sexual abuse/assault of persons with an intellectual disability is reported compared with 1 in 5 cases in the non-disabled population.	USA: S James "Sexual abuse of the handicapped" (1988) cited in Tharinger, Burrows Horton and Millea (1990) at 304.
55 cases of abuse occured over 33 month period in four facilities for intellectual disability with a combined population of approximately 1,000:40 physical abuse; 7 verbal abuse; 4 sexual abuse; 3 behavioural abuse; 1 neglect.	USA: Marchetti and McCartney (1990) at 368.
83% of women and 43% of men of people with intellectual disabilities had been sexually assaulted.	USA: S Hard Sexual abuse of the Developmentally Disabled: A Case Study (1986) cited in New South Wales - Women's Co-ordination Unit (1990) at 11.
100,000 people with disabilities were raped in the USA in 1981, and the rate of other forms of sexual assault was considerably higher than this.	USA: Centre for Women's Policy Studies "Sexual exploitation and abuse of people with disabilities" (1984) cited in New South Wales - Women's Co-ordination Unit (1990) at 11.
4-5% of patients of British consultants have suffered abuse, predominantly sexual.	UK: L Cooke "Abuse of mentally handicapped adults" (1990) cited in McCormack (1991) at 143.
10% of all children with an intellectual disability have suffered sexual abuse.	UK: A Baker and S Duncan "Child sex abuse: A study of prevalence i Great Britian" (1985) cited in McCormack (1991) at 143.
Of children with various levels of learning disability in a "subnormality" hospital: 22% were victims of physical abuse and 10% were at risk, and 11% could have been rendered learning disabled as a result of abuse.	UK: A Buchanan and J Oliver "Abuse and neglect as cause fo mental retardation: A study of 140 children admitted to sub-normality hospitals in Wiltshire (1977) in Westcott (1991) at 246.

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