By Karen Franklin, Ph.D.
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.
Published studies authored by tool designers reported predictive validity findings around two times higher than investigations by independent researchers, according to a systematic meta-analysis that included 30,165 participants in 104 samples from 83 independent studies.