Testing the Evaluation of the Testimony of the Global Evaluation System in Bullying Cases

Background/aim: The prevalence of school bullying victimization has been estimated between 5% (strict criteria for prevalence classification) and 33% (lenient criteria for prevalence assessment) of children and adolescents. Bullying victimization entails decision-making at the administrative (school setting), civil (victim compensation), and criminal (criminal responsibility) levels, which must be based on certainty about the truthfulness of the allegation. A high-fidelity simulation study was designed with the aim of testing the evaluation of testimony of the Global Evaluation System (GES) in cases of bullying allegations. Method: A total of 154 adolescents aged from 13 to 18 years, 86 boys, were randomly assigned to the condition of testimony of a memory of real-life negative experiences or a fabricated memory of a bullying event. The protocols (statements) were subjected to a content analysis using the categories of validity of the evidence and the content categories of memories of real-life experiences of the GES. Results: The results showed excellent reliability, α = .874, 95% CI [.843, .901], for the GES content category system. The findings also supported the association between the GES content categories and memories of real-life experiences. Conversely, no significant association was found between fabricated memories of a bullying event and the GES content categories, while a lack of reliability was observed, α = .476, 95% CI [.289, .632], in this condition. Finally, strict decision criteria were computed (evidence-based criterial validity) that guarantees compliance with the principle of presumption of innocence (no innocent person should be convicted; type I error/false positives = 0): coding of ≥ 10 content categories in the complete model, ≥ 8 in the higher-prevalence model (content categories associated significantly with memories of real-life experiences), and ≥ 5 in the robust model (content categories associated significantly with memories of real-life experiences with a moderate or higher than moderate effect size). Conclusions: These findings support the validity and reliability of the GES content analysis categorical system for the validation of truthful testimonies of school bullying victimization (forensic task), providing scientific evidence (criterial validity) to ensure the strict compliance of the principle of presumption of innocence, but not for the classification of fabricated memories (investigative task).