A Critical Evaluation of the Usefulness of Criteria-Based Content Analysis for Judging the Credibility of Public Appeals for Missing Persons

In criminal cases, the contradictory witness statements of an alleged victim and perpetrator(s) may be the only evidence available to the authorities. The current work investigated the usefulness of Criteria Based Content Analysis (CBCA), a credibility assessment or “truth detection” tool. Although CBCA was specifically designed for child witness statements in sexual abuse cases, it has since been argued that the method is effective when applied: i) to the statements of adults, ii) to statements unrelated to sexual abuse, and iii) as a method of lie detection. The current work intended to investigate these claims by applying both the original credibility criteria and an adapted version to adults’ statements from public appeals for missing people. Given the previous research emphasis on psychological and social psychological perspectives, however, the research brought to bear insights from broadly conceived discourse analytic methodology, utilising concepts from Gricean Pragmatics and Interactional Sociolinguistics. The results indicate that both sets of criteria are not suitable for use on this type of data. In particular, the efficacy of many credibility-related content characteristics is reduced when applied to public appeals, given that: i) the context of statement production differs from an interview about sexual abuse; ii) speakers produce their statements for a different purpose; and iii) crime victimisation narratives were absent in the majority of the public appeals in this dataset, rendering many criteria diagnostically irrelevant. The findings have important implications for the use of credibility criteria outside of the context for which they were designed. In real-life, high-stakes criminal cases, the development of more context-sensitive methods of deception detection and credibility assessment is recommended