Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, UK.
Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
Sci Rep. 2019 Jan 29;9(1):841. doi: 10.1038/s41598-018-37539-x.
Scalable and transparent methods for risk assessment are increasingly required in criminal justice to inform decisions about sentencing, release, parole, and probation. However, few such approaches exist and their validation in external settings is typically lacking. A total national sample of all offenders (9072 released from prisoners and 6329 individuals on probation) from 2011-2012 in the Netherlands were followed up for violent and any reoffending over 2 years. The sample was mostly male (n = 574 [6%] were female prisoners and n = 784 [12%] were female probationers), and median ages were 30 in the prison sample and 34 in those on probation. Predictors for a scalable risk assessment tool (OxRec) were extracted from a routinely collected dataset used by criminal justice agencies, and outcomes from official criminal registers. OxRec's predictive performance in terms of discrimination and calibration was tested. Reoffending rates in the Dutch prisoner cohort were 16% for 2-year violent reoffending and 44% for 2-year any reoffending, with lower rates in the probation sample. Discrimination as measured by the c-index was moderate, at 0.68 (95% CI: 0.66-0.70) for 2-year violent reoffending in prisoners and between 0.65 and 0.68 for other outcomes and the probation sample. The model required recalibration, after which calibration performance was adequate (e.g. calibration in the large was 1.0 for all scenarios). A recalibrated model for OxRec can be used in the Netherlands for individuals released from prison and individuals on probation to stratify their risk of future violent and any reoffending. The approach that we outline can be considered for external validations of criminal justice and clinical risk models.
在刑事司法中，越来越需要可扩展且透明的风险评估方法，以辅助量刑、释放、假释和缓刑等决策。然而，目前此类方法很少，且其在外部环境中的验证通常也较为缺乏。我们对 2011-2012 年荷兰所有罪犯（9072 名出狱犯人和 6329 名缓刑犯）进行了全国性随访，观察其在 2 年内的暴力和任何重新犯罪情况。该样本中大多数为男性（n=574[6%]为女性囚犯，n=784[12%]为女性缓刑犯），年龄中位数分别为监狱样本中的 30 岁和缓刑样本中的 34 岁。可扩展风险评估工具（OxRec）的预测因子从刑事司法机构使用的常规数据集和官方犯罪记录中提取，评估结果来自官方犯罪记录。我们对 OxRec 的预测性能（区分度和校准度）进行了测试。荷兰囚犯队列的再犯率为 2 年内暴力再犯率为 16%，任何再犯率为 44%，而缓刑样本中的再犯率较低。以 c 指数衡量的区分度为中度，监狱中 2 年内暴力再犯的 c 指数为 0.68（95%CI：0.66-0.70），其他结果和缓刑样本的 c 指数在 0.65 至 0.68 之间。该模型需要重新校准，之后校准性能较为理想（例如，在大样本中所有场景的校准度均为 1.0）。经重新校准的 OxRec 模型可用于荷兰出狱犯人和缓刑犯，以分层其未来暴力和任何再犯的风险。我们概述的方法可用于刑事司法和临床风险模型的外部验证。
