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Sex Offender Risk Assessment: Where Are We and Where Are We Going?


Purpose of Review

Risk assessment is one of the most ubiquitous tasks in the criminal justice system, informing virtually every decision made about offenders. This review, intended for researchers and practitioners, outlines some of the most important recent advances, emerging issues, and recommendations in sex offender risk assessment.

Recent Findings

The underlying nature and purpose of risk scales is reviewed, with implications for how we should evaluate them. Limits of recidivism probability estimates are discussed, and efforts to advance a common language for describing risk levels are highlighted. Advances in risk communication and field validity are summarized. The utility of protective risk factors in risk assessments is debated. Emerging areas in assessing offender change and assessments with child pornography offenders are discussed.


Despite critical advances in the last few years, there are still important gaps in knowledge, particularly for risk communication, field implementation, offender change, and child pornography offenders.

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Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

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    Helmus L, Hanson RK, Thornton D, Babchishin KM, Harris AJR. Absolute recidivism rates predicted by Static-99R and Static-2002R sex offender risk assessment tools vary across samples: a meta-analysis. Crim Justice Behav. 2012;39:1148–71. https://doi.org/10.1177/0093854812443648.

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    Helmus L. Re-norming Static-99 recidivism estimates: exploring base rate variability across sex offender samples (Master’s thesis). Available from ProQuest Dissertations and Theses database. (UMI No. MR58443) 2009.

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    Helmus L, Thornton D. The MATS-1 risk assessment scale: summary of methodological concerns and an empirical validation. Sex Abus. 2014;28:160–86. https://doi.org/10.1177/1079063214529801.

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    •• Hanson RK, Thornton D, Helmus LM, Babchishin KM. What sexual recidivism rates are associated with Static-99R and Static-2002R scores? Sex Abus. 2016;28:218–52. https://doi.org/10.1177/1079063215574710. This paper summarizes several years of research on the (in)stability of recidivism estimates for Static-99R and Static-2002R (a problem which is likely applicable to all actuarial scales). The paper includes detailed discussion of various options for dealing with the variability in recidivism estimates in applied reports, as well as their recommendations .

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    Levenson JS, Brannon YN, Fortney T, Baker J. Public perceptions about sex offenders and community protection policies. Anal Soc Issues Public Policy. 2007;7:137–61.

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    • Hilton NZ, Scurich N, Helmus LM. Communicating the risk of violent and offending behavior: Review and introduction to special issue. Behav Sci Law. 2015;33:1–18. https://doi.org/10.1002/bsl.2160. Detailed review of the field of offender risk communication, drawing heavily on research in medical risk communication .

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    •• Varela JG, Boccaccini MT, Cuervo VA, Murrie DC, Clark JW. Same score, different message: perceptions of offender risk depend on Static-99R risk communication format. Law Hum Behav. 2014;38:418–27. https://doi.org/10.1037/lhb0000073. Explored effectiveness of different risk communication methods with prospective jurors. Found nominal risk labels tended to have the strongest influence in risk perception among jurors. Other findings and interactions highlight areas for improvement in risk communication .

  31. 31.

    Helmus LM Developing and validating a risk assessment scale to predict inmate placements in administrative segregation in the Correctional Service of Canada. Doctoral dissertation, Carleton University, Ottawa, Canada 2015.

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    Quinsey VL, Harris GT, Rice ME, Cormier CA. Violent offenders: appraising and managing risk. 2nd ed. Washington, DC: American Psychological Association; 2006.

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    Langan PA, Levin DJ. Recidivism of prisoners released in 1994 (Bureau of Justice Statistics Special Report NCJ 193427). Washington, DC: US Department of Justice; 2002.

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    Barbaree HE, Langton CM, Peacock EJ. Different actuarial risk measures produce different risk rankings for sexual offenders. Sex Abus. 2006;18:423–40. https://doi.org/10.1007/s11194-006-9029-9.

  39. 39.

    Jung, S., Pham, A., & Ennis, L. (2013). Measuring the disparity of categorical risk among various sex offender risk assessment measures. The Journal of Forensic Psychiatry & Psychology, 24, 353–370. doi:https://doi.org/10.1080/14789949.2013.806567.

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    Mills JF, Kroner DG. The effect of discordance among violence and general recidivism risk estimates on predictive accuracy. Crim Behav Ment Health. 2006;16:155–66. https://doi.org/10.1002/cbm.623.

  41. 41.

    • Hanson RK, Babchishin KM, Helmus LM, Thornton D, Phenix A. Communicating the results of criterion-referenced prediction measures: risk categories for the Static-99R and Static-2002R sexual offender risk assessment tools. Psychol Assess. 2017;29:582–97. https://doi.org/10.1037/pas0000371. The first application of the Justice Center standardized 5-level risk framework, applied to Static-99R and Static-2002R. Includes broad review of the issue of defining and interpreting risk levels .

  42. 42.

    •• Hanson RK, Bourgon G, McGrath RJ, Kroner D, D’Amora DA, Thomas SS, et al. A five-level risk and needs system: maximizing assessment results in corrections through the development of a common language, Justice Center Council of State Governments. Washington, DC; 2016. Summarizes a multi-year initiative from an international advisory group to develop a standardized framework for describing offender risk. The proposed five-level risk/needs system will likely become a dominant language in offender risk assessment .

  43. 43.

    • Olver ME, Mundt JC, Thornton D, Beggs Christofferson SM, Kingston DA, Sowden JN, et al. Using the violence risk scale–sexual offense version in sexual violence risk assessments: updated risk categories and recidivism estimates from a multisite sample of treated sexual offenders. Psychol Assess. Advance online publication 2017. https://doi.org/10.1037/pas0000538. Psychological Assessment. Application of the Justice Center standardized 5-level risk framework to VRS-SO, which includes static risk, dynamic risk, and treatment change information 2018.

  44. 44.

    Brankley AE, Helmus LM, Hanson RK (2017). STABLE-2007 evaluator workbook—revised 2017. Ottawa, ON.

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    Hilton NZ, Ham E, Nunes KL, Rodrigues NC, Frank C, Seto MC. Using graphs to improve violence risk communication. Crim Justice Behav. 2017;44:678–94.

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    Robbé d V, de Vogel V, Douglas KS. Risk factors and protective factors: a two-sided dynamic approach to violence risk assessment. J Forensic Psychiatry Psychol. 2013;24:440–57.

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    • Robbé d V, Mann RE, Maruna S, Thornton D. An exploration of protective factors supporting desistance from sexual offending. Sex Abus. 2015;27:16–33. Influential review resulting in the proposal of eight potentially protective factors supporting desistance .

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    Farrington DP, Ttofi MM. Protective and promotive factors in the development of offending. In: Bliesener T, Beelmann A, Stemmler M, editors. Antisocial behavior and crime: contributions of developmental and evaluation research to prevention and intervention. Cambridge: Hogrefe Publishing; 2011. p. 71–88.

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    Andrews DA, Bonta J. The psychology of criminal conduct. 5th ed. Cincinnati: Lexus-Nexus; 2010.

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    Harris GT, Rice ME. Progress in violence risk appraisal and communication: a commentary on hypotheses and evidence. Behav Sci Law. 2015;33:128–45. https://doi.org/10.1002/bsl.2157.

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    Mann RE, Hanson RK, Thornton D. Assessing risk for sexual recidivism: some proposals on the nature of psychologically meaningful risk factors. Sex Abus. 2010;22:191–217. https://doi.org/10.1177/1079063210366039.

  52. 52.

    Hanson RK, Harris AJR, Scott T-L, Helmus L. Assessing the risk of sexual offenders on community supervision: the Dynamic Supervision Project. Ottawa: Public Safety Canada; 2007.

  53. 53.

    Olver ME, Wong SCP, Nicholaichuk TP, Gordon A. The validity and reliability of the Violence Risk Scale-Sexual Offender version: assessing sex offender risk and evaluating therapeutic change. Psychol Assess. 2007;19:318–29. https://doi.org/10.1037/1040-3590.19.3.318.

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    Olver ME, Nicholaichuk TP, Kingston DA, Wong SCP. A multisite examination of sexual violence risk and therapeutic change. J Consult Clin Psychol. 2014;82:312–24. https://doi.org/10.1037/a0035340.

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    • Olver ME, Beggs Christofferson SM, Wong SCP. Evaluation and applications of the clinically significant change method with the Violence Risk Scale-Sexual Offender version: implications for risk-change communication. Behav Sci Law. 2015;33:92–110. https://doi.org/10.1002/bsl.2159. Combining the limited research literature on both sex offender change and sex offender risk communication, this study empirically explores how the clinically significant change method can be used in risk communication for sex offenders .

  56. 56.

    Olver ME, Sowden JN, Kingston DA., Nicholaichuk TP, Gordon, A, Beggs Christofferson SM, Wong SCP. Predictive accuracy of Violence Risk Scale–Sexual Offender version risk and change scores in treated Canadian Aboriginal and non-Aboriginal sexual offenders. Sex Abus. 2018;30:254–275.

  57. 57.

    Babchishin KM (2013). Sex offenders do change on risk-relevant propensities: evidence from a longitudinal study of the ACUTE-2007. Unpublished doctoral dissertation, Carleton University, Ottawa, ON.

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    Mowen TJ, Culhane SE. Modeling recidivism within the study of offender reentry: hierarchical generalized linear models and lagged dependent variable models. Crim Justice Behav. 2017;44:85–102.

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    Yang M, Guo B, Olver ME, Polaschek DLL, Wong SCP. Assessing associations between changes in risk and subsequent reoffending: an introduction to relevant statistical models. Crim Justice Behav. 2017;44:59–84.

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    Hanson RK, Harris AJR, Helmus L, Thornton D. High risk sex offenders may not be high risk forever. J Interpers Violence. 2014;29:2792–813. https://doi.org/10.1177/0886260514526062.

  61. 61.

    • Hanson RK, Harris AJR, Letourneau E, Helmus LM, Thornton D. Reductions in risk based on time offense free in the community: Once a sex offender, not always a sex offender. Psychol Public Policy Law. 2018. This study empirically models the relationship between time offence-free and sexual recidivism, including exploration of covariates and interactions. Structured methods of adjusting Static-99R and Static-2002R risk levels based on time free are provided. These findings are used to criticize long-term sexual offender risk management policies that are insensitive to initial risk and time free effects .

  62. 62.

    Boccaccini MT, Murrie DC, Caperton JD, Hawes SW. Field validity of the Static-99 and MnSOST-R among sex offenders evaluated for civil commitment as sexually violent predators. Psychol Public Policy Law. 2009;15:278–314. https://doi.org/10.1037/a0017232.

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    • Hanson RK, Helmus LM, Harris AJR. Assessing the risk and needs of supervised sexual offenders: a prospective study using STABLE-2007, Static-99R, and Static-2002R. Crim Justice Behav. 2015;42:1205–24. https://doi.org/10.1177/0093854815602094. Field validity study of Static-99R, STABLE-2007, and ACUTE-2007. Contains important findings related to degradations in predictive accuracy associated with professional judgement overrides, and higher predictive accuracy for community supervision officers who submitted all the information requested of them, suggesting that quality of implementation can make a large difference in accuracy .

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    Rettenberger M, Haubner-Maclean T, Eher R. The contribution of age to the Static-99 risk assessment in a population-based prison sample of sexual offenders. Crim Justice Behav. 2013;40:1413–33. https://doi.org/10.1177/0093854813492518.

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    Hanson RK, Lunetta A, Phenix A, Neeley J, Epperson D. The field validity of Static-99/R sex offender risk assessment tool in California. J Threat Assess Manag. 2014;1:102–17. https://doi.org/10.1037/tam0000014.

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    • Boccaccini MT, Rice AK, Helmus LM, Murrie DC, Harris PB. Field validity of Static-99/R scores in a statewide sample of 34,687 convicted sexual offenders. Psychol Assess. 2017;29:611–23. https://doi.org/10.1037/pas0000377. By far the largest field validity study in sex offender risk assessment. Interesting findings include improvements in predictive accuracy and interrater reliability over time. Also includes analyses of ethnicity, comparisons to other field validity studies (these effect sizes are among the lowest), and proposes Texas-specific recidivism norms for Static-99R, which are roughly half the rate of the current routine correctional norms for Static-99R .

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  72. 72.

    Thornton D, Mann R, Webster S, Blud L, Travers R, Friendship C, et al. Distinguishing and combining risks for sexual and violent recidivism. Ann N Y Acad Sci. 2003;989(1):225–35. https://doi.org/10.1111/j.1749-6632.2003.tb07308.x.

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    •• Seto MC, Eke AW. Predicting recidivism among adult male child pornography offenders: Development of the Child Pornography Offender Risk Tool (CPORT). Law Hum Behav. 2015;39:416–229. https://doi.org/10.1037/lhb0000128. Summarizes the development of the first (and thus far, only) risk scale developed for child pornography offenders. Although preliminary and based on a small sample size, this simple 7-item static scale appears to hold promise for child pornography offender risk assessment .

  75. 75.

    Eke AW, Helmus LM, Seto MC. A validation of the Child Pornography Offender Risk Tool (CPORT). Sexual Abus. Advance online publication 2018.

  76. 76.

    Eke AW, Seto MC. Scoring Guide for the Child Pornography Offender Risk Tool (CPORT). Unpublished document 2016. Available at https://www.researchgate.net/project/Child-Pornography-Offender-Risk-Tool-CPORT

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I would like to thank Stacey Kosega and Elsemiek Griemink for their assistance with references.

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Correspondence to L. Maaike Helmus.

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L. Maaike Helmus declares no conflict of interest.

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Helmus, L.M. Sex Offender Risk Assessment: Where Are We and Where Are We Going?. Curr Psychiatry Rep 20, 46 (2018). https://doi.org/10.1007/s11920-018-0909-8

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  • Risk assessment
  • Sexual offenders
  • Recidivism
  • Prediction
  • Offender assessment