Forensic assessment may be based on common sense assumptions rather than science

Abstract Forensic assessments must be scientifically founded, because courts should obtain expert evidence with acceptable evidential value. In Slovenia, professional guidelines of forensic personality assessment are too general and not always in line with international professional recommendations. Thus, experts have no strict guidelines which would lead them to scientifically grounded expert opinions. The aim of the research was to establish which tests are employed in forensic assessment in Slovenia and to what extent the professional guidelines for expert opinions are followed. A total of 166 forensic personality assessments were reviewed, representing the majority of expert opinions issued in the period 2003–2018. The results of the analysis revealed that questionable projective tests are most commonly used. Typically, an expert opinion was rendered based on two tests, at least one of which was projective. What is more, expert opinions did not include hypotheses, in-text citations, reference lists, or proof of the expert witness's competence. The tests and their results were mentioned briefly and inadequately, without mention of their reliability and validity. Possible malingering of the person being evaluated was not detected. Professional guidelines were not followed and non-standardized tests without normative values and of questionable scientific merit were predominantly used, despite lack of proof that they truly measure what they claim to be measuring. These findings significantly differ from the results of similar research, raising serious concerns over the credibility of expert opinions in Slovenia.