Authorship bias in violence risk assessment? A systematic review and meta-analysis.

Various financial and non-financial conflicts of interests have been shown to influence the reporting of research findings, particularly in clinical medicine. In this study, we examine whether this extends to prognostic instruments designed to assess violence risk. Such instruments have increasingly become a routine part of clinical practice in mental health and criminal justice settings. The present meta-analysis investigated whether an authorship effect exists in the violence risk assessment literature by comparing predictive accuracy outcomes in studies where the individuals who designed these instruments were study authors with independent investigations. A systematic search from 1966 to 2011 was conducted using PsycINFO, EMBASE, MEDLINE, and US National Criminal Justice Reference Service Abstracts to identify predictive validity studies for the nine most commonly used risk assessment tools. Tabular data from 83 studies comprising 104 samples was collected, information on two-thirds of which was received directly from study authors for the review. Random effects subgroup analysis and metaregression were used to explore evidence of an authorship effect. We found a substantial and statistically significant authorship effect. Overall, studies authored by tool designers reported predictive validity findings around two times higher those of investigations reported by independent authors (DOR=6.22 [95% CI=4.68-8.26] in designers' studies vs. DOR=3.08 [95% CI=2.45-3.88] in independent studies). As there was evidence of an authorship effect, we also examined disclosure rates. None of the 25 studies where tool designers or translators were also study authors published a conflict of interest statement to that effect, despite a number of journals requiring that potential conflicts be disclosed. The field of risk assessment would benefit from routine disclosure and registration of research studies. The extent to which similar conflict of interests exists in those developing risk assessment guidelines and providing expert testimony needs clarification.