Reported predictive validity higher in studies by an instrument's designers than by independent researchers
The use of actuarial risk assessment instruments to predict violence is becoming more and more central to forensic psychology practice. And clinicians and courts rely on published data to establish that the tools live up to their claims of accurately separating high-risk from low-risk offenders.
But as it turns out, the predictive validity of risk assessment instruments such as the Static-99 and the VRAG depends in part on the researcher's connection to the instrument in question.
|Publication bias in pharmaceutical research|
has been well documented
Conflicts of interest shrouded
Compounding the problem, in not a single case did instrument designers openly report this potential conflict of interest, even when a journal's policies mandated such disclosure.
As the study authors point out, an instrument’s designers have a vested interest in their procedure working well. Financial profits from manuals, coding sheets and training sessions depend in part on the perceived accuracy of a risk assessment tool. Indirectly, developers of successful instruments can be hired as expert witnesses, attract research funding, and achieve professional recognition and career advancement.
These potential rewards may make tool designers more reluctant to publish studies in which their instrument performs poorly. This "file drawer problem," well established in other scientific fields, has led to a call for researchers to publicly register intended studies in advance, before their outcomes are known.
The researchers found no evidence that the authorship effect was due to higher methodological rigor in studies carried out by instrument designers, such as better inter-rater reliability or more standardized training of instrument raters.
"The credibility of future research findings may be questioned in the absence of measures to tackle these issues," the authors warn. "To promote transparency in future research, tool authors and translators should routinely report their potential conflict of interest when publishing research investigating the predictive validity of their tool."
The meta-analysis examined all published and unpublished research on the nine most commonly used risk assessment tools over a 45-year period:
- Historical, Clinical, Risk Management-20 (HCR-20)
- Level of Service Inventory-Revised (LSI-R)
- Psychopathy Checklist-Revised (PCL-R)
- Spousal Assault Risk Assessment (SARA)
- Structured Assessment of Violence Risk in Youth (SAVRY)
- Sex Offender Risk Appraisal Guide (SORAG)
- Sexual Violence Risk-20 (SVR-20)
- Violence Risk Appraisal Guide (VRAG)
Although the researchers were not able to break down so-called "authorship bias" by instrument, the effect appeared more pronounced with actuarial instruments than with instruments that used structured professional judgment, such as the HCR-20. The majority of the samples in the study involved actuarial instruments. The three most common instruments studied were the Static-99 and VRAG, both actuarials, and the PCL-R, a structured professional judgment measure of psychopathy that has been criticized criticized for its vulnerability to partisan allegiance and other subjective examiner effects.
This is the latest important contribution by the hard-working team of Jay Singh of Molde University College in Norway and the Department of Justice in Switzerland, (the late) Martin Grann of the Centre for Violence Prevention at the Karolinska Institute, Stockholm, Sweden and Seena Fazel of Oxford University.
A goal was to settle once and for all a dispute over whether the authorship bias effect is real. The effect was first reported in 2008 by the team of Blair, Marcus and Boccaccini, in regard to the Static-99, VRAG and SORAG instruments. Two years later, the co-authors of two of those instruments, the VRAG and SORAG, fired back a rebuttal, disputing the allegiance effect finding. However, Singh and colleagues say the statistic they used, the receiver operating characteristic curve (AUC), may not have been up to the task, and they "provided no statistical tests to support their conclusions."
Prominent researcher Martin Grann dead at 44
Sadly, this will be the last contribution to the violence risk field by team member Martin Grann, who has just passed away at the young age of 44. His death is a tragedy for the field. Writing in the legal publication Das Juridik, editor Stefan Wahlberg noted Grann's "brilliant intellect" and "genuine humanism and curiosity":
Martin Grann came in the last decade to be one of the most influential voices in both academic circles and in the public debate on matters of forensic psychiatry, risk and hazard assessments of criminals and ... treatment within the prison system. His very broad knowledge in these areas ranged from the law on one hand to clinical therapies at the individual level on the other -- and everything in between. This week, he would also debut as a novelist with the book "The Nightingale."
The article, Authorship Bias in Violence Risk Assessment? A Systematic Review and Meta-Analysis, is freely available online via PloS ONE (HERE).
Related blog reports:
- Violence risk instruments overpredicting danger (Aug. 2, 2012)
- Violence risk in schizophrenics: Are forensic tools reliable predictors? (Sept. 14, 2011)
- Violence risk meta-meta: Instrument choice does matter (June 19, 2011)
- Psychology rife with inaccurate research findings (Nov. 20, 2011)
- International violence risk researchers launch free news service (June 13, 2013)