Predicting Violence and Antisocial Behavior
Predicting Violence and Antisocial Behavior
Objective To investigate the predictive validity of tools commonly used to assess the risk of violence, sexual, and criminal behaviour.
Design Systematic review and tabular meta-analysis of replication studies following PRISMA guidelines.
Data sources PsycINFO, Embase, Medline, and United States Criminal Justice Reference Service Abstracts.
Review methods We included replication studies from 1 January 1995 to 1 January 2011 if they provided contingency data for the offending outcome that the tools were designed to predict. We calculated the diagnostic odds ratio, sensitivity, specificity, area under the curve, positive predictive value, negative predictive value, the number needed to detain to prevent one offence, as well as a novel performance indicator—the number safely discharged. We investigated potential sources of heterogeneity using metaregression and subgroup analyses.
Results Risk assessments were conducted on 73 samples comprising 24,847 participants from 13 countries, of whom 5879 (23.7%) offended over an average of 49.6 months. When used to predict violent offending, risk assessment tools produced low to moderate positive predictive values (median 41%, interquartile range 27-60%) and higher negative predictive values (91%, 81-95%), and a corresponding median number needed to detain of 2 (2-4) and number safely discharged of 10 (4-18). Instruments designed to predict violent offending performed better than those aimed at predicting sexual or general crime.
Conclusions Although risk assessment tools are widely used in clinical and criminal justice settings, their predictive accuracy varies depending on how they are used. They seem to identify low risk individuals with high levels of accuracy, but their use as sole determinants of detention, sentencing, and release is not supported by the current evidence. Further research is needed to examine their contribution to treatment and management.
With the increasing recognition of the public health importance of violence, the prediction of violence, or violence risk assessment, has been the subject of considerable clinical and research interest. Since the late 1980s, such assessment has mostly been conducted by structured instruments after several studies found unstructured clinical opinion to have little evidence in support. Recent surveys have estimated that over 60% of general psychiatric patients are routinely assessed for violence risk, rising to above 80% in forensic psychiatric hospitals.
The widespread use of these tools has been partly driven by public concern about the safety of mentally ill patients, research evidence that severe mental illness is associated with violence, and clinical practice guidelines in some countries, including the United Kingdom and United States, recommending violence risk assessment for all patients with schizophrenia. Furthermore, criminal justice systems in many countries have welcomed the use of risk assessment to assist sentencing and release decisions. Risk assessment has been used to inform indeterminate sentencing in the UK, and has become a largely uncontested part of an expanded criminal justice process in the US. Furthermore, a 2004 survey reported that of the 32 US states where parole is an option, 23 had used such instruments as part of these decisions.
The current group of risk assessment tools either provide a probabilistic estimate of violence risk in a specified time period (actuarial instruments), or allow for a professional judgment to be made on risk level (for example, low, moderate, or high) after taking into account the presence or absence of a predetermined set of factors (structured clinical judgment instruments). Over 150 of these structured measures currently exist, and are starting to be implemented in low and middle income countries.
However, these tools are time consuming and resource intensive, typically taking many hours to complete by a multidisciplinary group of professionals. They can also be expensive; training is required for most tools, and payment is often needed for individual use. Further, and more importantly, the instruments’ predictive accuracy remains a source of considerable uncertainty, with some reviews recommending their use in clinical and correctional settings and others finding that they lead to an unacceptably high number of false positive decisions. Expert opinion is equally divided.
We have therefore conducted a systematic review and meta-analysis of the predictive accuracy of the most commonly used risk assessment instruments. To consistently report outcomes for individual studies, we requested tabular data from primary authors. We have synthesised these data across a range of accuracy estimates, one of which was developed for the purposes of this review.
Abstract and Introduction
Abstract
Objective To investigate the predictive validity of tools commonly used to assess the risk of violence, sexual, and criminal behaviour.
Design Systematic review and tabular meta-analysis of replication studies following PRISMA guidelines.
Data sources PsycINFO, Embase, Medline, and United States Criminal Justice Reference Service Abstracts.
Review methods We included replication studies from 1 January 1995 to 1 January 2011 if they provided contingency data for the offending outcome that the tools were designed to predict. We calculated the diagnostic odds ratio, sensitivity, specificity, area under the curve, positive predictive value, negative predictive value, the number needed to detain to prevent one offence, as well as a novel performance indicator—the number safely discharged. We investigated potential sources of heterogeneity using metaregression and subgroup analyses.
Results Risk assessments were conducted on 73 samples comprising 24,847 participants from 13 countries, of whom 5879 (23.7%) offended over an average of 49.6 months. When used to predict violent offending, risk assessment tools produced low to moderate positive predictive values (median 41%, interquartile range 27-60%) and higher negative predictive values (91%, 81-95%), and a corresponding median number needed to detain of 2 (2-4) and number safely discharged of 10 (4-18). Instruments designed to predict violent offending performed better than those aimed at predicting sexual or general crime.
Conclusions Although risk assessment tools are widely used in clinical and criminal justice settings, their predictive accuracy varies depending on how they are used. They seem to identify low risk individuals with high levels of accuracy, but their use as sole determinants of detention, sentencing, and release is not supported by the current evidence. Further research is needed to examine their contribution to treatment and management.
Introduction
With the increasing recognition of the public health importance of violence, the prediction of violence, or violence risk assessment, has been the subject of considerable clinical and research interest. Since the late 1980s, such assessment has mostly been conducted by structured instruments after several studies found unstructured clinical opinion to have little evidence in support. Recent surveys have estimated that over 60% of general psychiatric patients are routinely assessed for violence risk, rising to above 80% in forensic psychiatric hospitals.
The widespread use of these tools has been partly driven by public concern about the safety of mentally ill patients, research evidence that severe mental illness is associated with violence, and clinical practice guidelines in some countries, including the United Kingdom and United States, recommending violence risk assessment for all patients with schizophrenia. Furthermore, criminal justice systems in many countries have welcomed the use of risk assessment to assist sentencing and release decisions. Risk assessment has been used to inform indeterminate sentencing in the UK, and has become a largely uncontested part of an expanded criminal justice process in the US. Furthermore, a 2004 survey reported that of the 32 US states where parole is an option, 23 had used such instruments as part of these decisions.
The current group of risk assessment tools either provide a probabilistic estimate of violence risk in a specified time period (actuarial instruments), or allow for a professional judgment to be made on risk level (for example, low, moderate, or high) after taking into account the presence or absence of a predetermined set of factors (structured clinical judgment instruments). Over 150 of these structured measures currently exist, and are starting to be implemented in low and middle income countries.
However, these tools are time consuming and resource intensive, typically taking many hours to complete by a multidisciplinary group of professionals. They can also be expensive; training is required for most tools, and payment is often needed for individual use. Further, and more importantly, the instruments’ predictive accuracy remains a source of considerable uncertainty, with some reviews recommending their use in clinical and correctional settings and others finding that they lead to an unacceptably high number of false positive decisions. Expert opinion is equally divided.
We have therefore conducted a systematic review and meta-analysis of the predictive accuracy of the most commonly used risk assessment instruments. To consistently report outcomes for individual studies, we requested tabular data from primary authors. We have synthesised these data across a range of accuracy estimates, one of which was developed for the purposes of this review.
Source...