The MATS-1 Risk Assessment Scale: Summary of Methodological Concerns and an Empirical Validation

The key role of base rates: systematic review and meta-analysis of the predictive value of four risk assessment instruments

AIMS OF THE STUDY

Many countries have seen a decline in recidivism rates over the past decades. These base rates are pertinent information for assessing the recidivism risk of offenders. They provide a foundation for clinical assessment and an empirical basis for risk assessment instrument norms, which inform expected recidivism rates. The present study explored the extent to which base rates influence the validity of risk assessment instruments.

METHODS

We systematically reviewed the available evidence on the discrimination ability of four well-established risk assessment instruments used to estimate the probability of recidivism for general (Level of Service Inventory-Revised [LSI-R]), violent (Violence Risk Appraisal Guide [VRAG]), sexual (Static-99R), and intimate partner violent offences (Ontario Domestic Assault Risk Assessment [ODARA]). We conducted a bivariate logit-normal random effects meta-analysis of sensitivity and false positive rates and modelled the positive and negative predictive values. We used base rates as reported in (a) the construction samples of each risk assessment instrument and (b) recent official statistics and peer-reviewed articles for different offence categories and countries. To assess the risk of bias, we used the Joanna Briggs Institute Critical Appraisal Checklist for Diagnostic Test Accuracy Studies.

RESULTS

We screened 644 studies and subsequently analysed 102, of which 96 were included in the systematic review and 24 in the meta-analyses. Discrimination was comparable for all four instruments (median area under the curve = 0.68-0.71). The information needed to calculate summary statistics of sensitivity and false positive rate was often not reported, and a risk of bias may be present in up to half of the studies. The largest summary sensitivity and false positive rate were estimated for the ODARA, followed by the LSI-R, the VRAG, and the Static-99R. If base rates are low, positive predictive values tend to be relatively low, while negative predictive values are higher: positive predictive value = 0.032-0.133 and negative predictive value = 0.985-0.989 for sexual offences; positive predictive value = 188-0.281 and negative predictive value = 0.884-0.964 for intimate partner violence; positive predictive value = 0.218-0.241 and negative predictive value = 0.907-0.942 for violent offences; positive predictive value = 0.335-0.377 and negative predictive value = 0.809-0.810 for general offences.

CONCLUSIONS

When interpreting the results of individual risk assessments, it is not sufficient to provide the discrimination of the instrument; the risk statement must also address the positive predictive value and discuss its implications for the specific case. As recidivism rates are neither stable over time nor uniform across countries or samples, the primary interpretation of risk assessment instruments should rely on the percentile rank. Expected recidivism rates should be interpreted with caution. However, our results are drawn from a limited database, as studies not reporting sufficient information were excluded from analyses and it was only possible to identify current base rates for modelling positive and negative predictive values for certain countries. International standards for consistently collecting and reporting base rates are important to better identify crime trends. Future research on the validity of risk assessment instruments should follow rigorous reporting standards.

Sex Offender Recidivism: Some Lessons Learned From Over 70 Years of Research

Sex offender recidivism (SOR) has been the subject of research for over 70 years. Myths, misconceptions, and erroneous conclusions about SOR, however, remain widespread, impeding the development of evidence-based policies aimed at preventing sexual offenses. To address the rich but uneven literature, a comprehensive review was conducted making it possible to provide a contextualized overview of scientific knowledge against the backdrop of methodological issues, challenges, and shortcomings. Over the years, researchers have been asked to provide a simple answer to a seemingly simple question: what are the recidivism rates for sexual offending? In response, the field has produced a wide range of findings making it difficult to draw firm conclusions, leaving room for interpretation and personal biases. The variations in recidivism rates are attributable to offender and methodological characteristics, both of which are embedded in a particular sociolegal context. As a result, the base rate of SOR is more effectively considered in terms of a series of questions that should include the type of recidivism, with whom, over what period, and in what context. Issues and debates that have marked the field and fueled its growth are highlighted. Research innovations and important areas of research are also discussed.

Older Individuals Convicted of Sexual Offenses: A Literature Review

The population of older individuals convicted of sexual offenses (OSOs) is rapidly increasing. However, we have little understanding of their characteristics (e.g., demographic, psychological, individual, offense, and risk) and needs. To identify any similarities or differences that are unique to older individuals convicted of sexual offending, it is important to compare such characteristics across the adult lifespan. Therefore, the aim of this systematic review was to specify and synthesize the current knowledge of characteristics across the adult lifespan of the population of individuals convicted of sexual offenses. Five databases were searched and 10,680 results were screened, resulting in 100 studies included in the final review. The findings were grouped into four emergent themes: age of onset and prevalence; offender and offense characteristics; age and the risk of reoffending; and treatment. Implications of the findings from this review are discussed in relation to future research and clinical practice.

Estimating the probability of sexual recidivism among men charged or convicted of sexual offences: Evidence-based guidance for applied evaluators

Risk assessment is routinely applied in forensic decision-making. Although relative risk information from risk scales is robust across diverse samples and settings, estimates of the absolute probability of sexual recidivism are not. Nonetheless, absolute recidivism estimates are still necessary in some evaluations. This paper summarizes research and offers guidance on evidence-based practices for assessing the probability of recidivism, organized largely around questions commonly asked in court. Overall, estimating the probability of sexual recidivism is difficult and should be undertaken with humility and circumspection. That being said, research favours empirical-actuarial risk tools for this task, more structured scales, and the use of multiple scales. Professional overrides of risk scale results should not be used under any circumstances. Paradoxically, however, professional judgement is still required in some circumstances. Risk scales do not consider all relevant risk factors, but the added value of external risk factors reaches a point of diminishing returns and may or may not be incremental (or worse, can degrade accuracy). There are reasons actuarial risk scales may both underestimate recidivism (e.g., undetected offending, short follow-ups) and overestimate recidivism (e.g., inclusion of sex offences not of interest in some referral questions, data on declining crime and recidivism rates, newer studies demonstrating overestimation of recidivism). Given all these considerations and the need for humility, in the absence of exceptional circumstances, I would not deviate too far from empirical estimates.

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.