Probability of Criminal Acts of Violence: A Test of Jury Predictive Accuracy

Abstract

The ability of capital juries to accurately predict future prison violence at the sentencing phase of aggravated murder trials was examined through retrospective review of the disciplinary records of 115 male inmates sentenced to either life (n = 65) or death (n = 50) in Oregon from 1985 through 2008, with a mean post-conviction time at risk of 15.3 years. Violent prison behavior was completely unrelated to predictions made by capital jurors, with bidirectional accuracy simply reflecting the base rate of assaultive misconduct in the group. Rejection of the special issue predicting future violence enjoyed 90% accuracy. Conversely, predictions that future violence was probable had 90% error rates. More than 90% of the assaultive rule violations committed by these offenders resulted in no harm or only minor injuries.

Prison Homicide: An Extension of Violent Criminal Careers?

“…The lower the base rate, the greater the likelihood of false positive identification and unnecessary classification to higher security. Studies have clearly shown that psychologists, prosecutors, and juries cannot reliably identify an inmate’s propensity to violence, and are wrong nearly all the time (Cunningham, Sorensen, & Reidy, 2009; Cunningham et al, 2010; Edens, Buffington-Vollum, Keilen, Ruskamp, & Anthony, 2005; Reidy, Sorensen, & Cunningham, 2013). Attempting to predict a prison homicide is even more perilous.…”

Wasted resources and gratuitous suffering: The failure of a security rationale for death row.

“…Despite the intuitive appeal of this logic, empirical findings reveal that neither the assertion of future dangerousness by the prosecution nor a finding of future dangerousness by a capital jury is predictive of serious prison violence or escape. This has been a consistent finding among federal capital offenders alleged pretrial by the Government to be a “future danger,” but subsequently sentenced to life-without-parole (Cunningham, Sorensen, & Reidy, 2009); Texas inmates sentenced to death under a “future dangerousness” special issue and subsequently gaining relief from these sentences (Cunningham, Sorensen, Vigen, & Woods, 2010; Edens, Buffington-Vollum, Keilen, Roskamp, & Anthony, 2005; Marquart, Ekland-Olson, & Sorensen, 1989); and CP inmates in Oregon who had been prosecuted under a “future dangerousness” special issue (i.e., whether there is a probability the defendant would commit criminal acts of violence that would constitute a continuing threat to society) and subsequently sentenced to death or life-without-parole (Reidy, Sorensen, & Cunningham, 2013). In all of these studies, only a small and not disproportionate minority of inmates who had faced capital charges committed assaults with the potential for serious injury.…”

Death is different: Reply to Olver et al. (2020).

“…7Of course, the precision and accuracy of predictions of serious institutional violence made using such an evaluation would itself be a matter for debate. We refer readers to Cunningham et al (2009) and other research concluding that with a very low base rate of serious prison violence among capital offenders and the dynamic responses of corrections staff, any mental health methodology predicting a probability of serious prison violence by a capital defendant will have a very high error rate (e.g., Cunningham, Reidy, & Sorensen, 2016; Cunningham & Sorensen, 2010; Cunningham, Sorensen, Vigen, & Woods, 2011; Edens, Buffington-Vollum, Keilen, Roskamp, & Anthony, 2005; Reidy, Sorensen, & Cunningham, 2012, 2013; Sorensen & Cunningham, 2010). …”