Executive Summary

By Dr Nick Wilson & Rehina Rolleston
Department of Corrections
Psychological Service
January 2004

The area of youth offender risk assessment and treatment is one that has received a lot of attention, both from the public and from correctional authorities. Violent crime by delinquent youth has increased markedly from the 1980s, with juvenile offenders often described as a vulnerable, multi-problem population, with high co-occurring rates of psychiatric; substance abuse, and abuse issues.

Youth have the highest rate of recidivism compared to other age brackets with 24.5% being reimprisoned within six months after release and 71.5% reimprisoned within five years. Violence amongst youth is also on the rise. The number of New Zealand youth apprehended for violent offences increased by 21% between 1994 and 2001 and approximately a quarter of all proven cases in New Zealand involving youth were for violence. There is therefore a need to apply the advancements made in risk assessment to youth offender populations, as it is among the delinquent youth of today that we are likely to find the chronic offenders of tomorrow.

This is the first research that has sought to gather information on a New Zealand incarcerated youth offender population from actuarial measures containing both static and dynamic risk factors. This was designed to allow the Department to develop a risk-need profile of youth offenders within the Young Offender Units (YOU) to enable targeted intervention to be developed. Youth offenders in the Hawkes Bay, Waikeria, and Christchurch YOU’s were administered a structured interview that allowed three specific risk measures to be scored from this information and analysed along with RoC*RoI scores for the group and offence related variables.

The key findings from the study are:

Sample/offence related variables

  • The ethnicity of the 69 participants in the study was evenly split between European and Maori although this differed between the three YOU’s in the study with the Waikeria YOU having the largest percentage of Maori and the Christchurch unit the largest percentage of European inmates;
  • The average age of participants at first conviction was 15.62 years of age with the mean current age when assessed in this study 17.5. The Waikeria unit was found to have a lower current mean age than the other two units;
  • Participants had a mean sentence length of 2 years 8 months with the most frequent index offences for Aggravated Robbery followed by Dishonesty. However, when all violent and sexual crimes were added, 70% had index offences for serious violence/sexual offending. No significant differences were found between the units for index offences;
  • They had a mean of 17 total convictions (both past and current), with a mean number of four different offences types (criminal versatility). Mean total violent convictions were 2.20, and sexual 0.43. Those in the Hawkes Bay and Christchurch units were found to have significantly higher means for total convictions and criminal versatility, variables related to higher risk of recidivism than the Waikeria unit.

Risk measures

  • All four measures were found to have a normal score distribution, although with a positive skew reflecting the high mean risk scores;
    • RoC*RoI (M = 0.58, SD = 0.17)
    • PCL: YV (M = 25.09, SD = 7.29)
    • RSYO (M = 38.48, SD = 12.97)
    • YLS/CMI (M = 23.49, SD 6.38)
  • All risk measures identified a proportion of the sample as high risk with both the RoC*RoI and PCL: YV identifying approximately 30%, the RSYO 10%, and the YSL/CMI 62% in this risk category;
  • The PCL: YV was the only risk measure that differed in mean score between units. The Hawkes Bay and Christchurch units were found to have significantly higher mean scores for this instrument than the Waikeria unit.

Distribution of dynamic risk factors

  • The YLS/CMI’s inclusion of dynamic risk factors identified the following percentage of the sample as having high rated dynamic needs:
    • Family 20%
    • Education/employment 78.5%
    • Peer relations 58%
    • Substance abuse 74%
    • Leisure/recreation 33%
    • Personality/behavior 42%
    • Attitudes/orientation 32%
  • Seventy-one percent of the sample had high scores for PCL: YV Factor 2: Affective deficits (i.e., lack of remorse, shallow affect, callous/lack of empathy, fails to accept responsibility);
  • Eighty percent of the sample had high scores for PCL: YV Factor 3: Behavioral deficits (i.e., Stimulation seeking, impulsivity, irresponsible, parasitic orientation, lacks goals).

Validity of risk measures

  • Moderate correlations were found for all risk measures and the offence related variables, total convictions and criminal versatility. The strongest for both being the RoC*RoI and PCL: YV scores;
  • Only the PCL: YV (r = .35) and RoC*RoI (r = .25) scores were found to have significant correlations with total violent convictions;
  • Moderate correlations were found between all measures, with the RSYO having a moderate/high relationship with all other measures. This was encouraging in view of the RoC*RoI, PCL: YV, and YLS/CMI all being proven predictors of recidivism and violence.


  • The study has established a risk-needs profile for a representative sample of imprisoned youth offenders from YOU’s. The four risk measures, RoC*RoI, PCL: YV, RSYO, and YLS/CMI were found to distinguish a range of risk and to have significant correlations with offence variables and each other. Besides identifying that the majority of offenders were imprisoned for serious violent/sexual offences a number of criminogenic needs were identified in the sample.
  • While youth offenders were imprisoned for serious or repeated crimes their sentence lengths in the main were relatively short, especially with most eligible for parole after a third of their sentence.
    • Therefore, any intervention to address their offending needs to be flexible and targeted at the highest priority criminogenic need.
    • While group treatment is the norm to ensure the greatest number receive treatment, short periods of imprisonment, high risk, and a range of index offence (including 14.5% for sexual offences) mean individual specialist psychological treatment services are required.
    • While some of the dynamic needs can be addressed through targeted psychological interventions others will require inclusion in a comprehensive reintegration plan. For example employment or association with antisocial peers.
  • That in view of the high number of the sample with violent index offences a targeted and intensive youth violence prevention programme is developed for use in the YOU’s;
  • The four risk measures used in this study were all found to identify a range of risk in the sample, with three, the PCL: YV, RoC*RoI and YLS/CMI classifying at least 30-60% as at high risk of further serious recidivism. The use of multiple measures of risk is recommended to reduce decision error when treatment is being targeted at those in greatest need.
  • It is recommended based on the results that RoC*RoI, YLS/CMI, and the RSYO are used with all youth offenders to identify those at high risk. The YLS/CMI and RSYO can be scored from a short 30-40 minute interview by trained PPS staff.
  • If further evidence of high risk is required by parole authorities or to support a Section 107 application (Parole Act 2002), especially for risk of violence, then the PCL: YV should be administered by trained departmental psychologists.
  • Finally, convergent validity has been found for the four measures based on their relationship with offence related variables and the strong correlations between the established specialist youth risk instruments (PCL; YV and YLS/CMI) and the New Zealand instruments (RoC*RoI; RSYO). However, validity will only be confirmed when predictive validity is established for the risk measures and the study sample (i.e., how good were the risk measure scores at predicting reoffending outcomes);
  • It is recommended that the sample is followed up again in approximately a years time when it is estimated that at least 70-80% of will have been release for a minimum of six months to provide some preliminary data on predictive validity.