https://doi.org/10.1177/0886260520914555
Journal of Interpersonal Violence
1–28
© The Author(s) 2020
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DOI: 10.1177/0886260520914555
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Original Research
Improving Risk
Communication:
Developing Risk Ratios
for the VRAG-R
Simon T. Davies, PhD, LLB, BSc(Hons),
1
L. Maaike Helmus, PhD,
2
and Vernon L. Quinsey, PhD
3
Abstract
We developed a set of risk ratios for the Violence Risk Appraisal Guide—
Revised (VRAG-R) to broaden the range of risk communication options
available when using this tool and to provide information needed for
future efforts to apply The Council of State Governments Justice Center’s
standardized five-level risk framework to the scale. A slightly reduced version
of the VRAG-R normative data set was used for the analyses (N = 1,238).
Contrary to previous research developing risk ratios, logistic regression
provided a more accurate estimate of observed violent recidivism rates than
Cox regression for both total VRAG-R scores and VRAG-R decile bins.
Further analyses indicated the relationship between the VRAG-R and violent
recidivism was consistent over a 15-year follow-up period. Due to the
difficulties with interpreting odds ratios, the final risk ratios were computed
using rate ratios derived from a logistic regression model using a 5-year fixed
follow-up period. These risk ratios, and templates for how the ratios might
be used in an assessment report, are presented in the appendices.
1
Victoria University of Wellington, New Zealand
2
Simon Fraser University, Burnaby, British Columbia, Canada
3
Queen’s University, Kingston, Ontario, Canada
Corresponding Author:
Simon T. Davies, School of Psychology, Victoria University of Wellington, P.O. Box 600,
Wellington 6140, New Zealand.
Email: simonthomasdavies@gmail.com
914555JIV XX X 10.1177/0886260520914555Journal of Interpersonal ViolenceDavies et al.
research-article 2020