This study examines procedures of statement analysis used to assess the credibility of statements in criminal investigation and trial, and experimentally tests how the way analytic hypotheses are specified—one of the core components of these procedu...
This study examines procedures of statement analysis used to assess the credibility of statements in criminal investigation and trial, and experimentally tests how the way analytic hypotheses are specified—one of the core components of these procedures—affects the outcomes of statement evaluation. On this basis, the study aims to propose avenues for the procedural refinement of statement analysis. Previous research and practice in statement analysis have largely relied on checklists such as Criteria-Based Content Analysis (CBCA) and Reality Monitoring (RM), while paying relatively little attention to procedural questions of which hypothesis is adopted, which episode is set as the analytical unit, and which cues are to be examined within that episode. In response, the present study defines an analytic hypothesis as a working hypothesis that specifies in advance the experiential cues expected in a specific episode, and stepwise investigates the relationships among the form of the analytic hypothesis (broad vs. specific), the procedure of statement analysis, and its scope of application through literature review, case studies, and an experimental study.
The literature review systematically examines the theoretical foundations of Statement Validity Assessment (SVA), RM, and investigative interviewing techniques, and confirms that the essence of statement analysis lies not in the tools themselves but in the procedural logic that predefines which episode is set as the unit of evaluation and which indicators should be observed within that episode. It also proposes that the scope of application of statement analysis should be determined by the presence of episodic content and the structural quality of the statement, rather than by legal categories such as victim vs. suspect or sexual vs. non‑sexual offences. The case studies comparatively analyse victim statements in sexual assault cases, suspect statements from the same cases, and adult victim statements in non‑sexual offences.
The results show that, despite differences in offence types and speakers, the same analytic structure—scene setting, cue examination, and validity assessment based on a specific analytic hypothesis—can be consistently applied. This demonstrates empirically that statement analysis is not confined to particular crime types or speaker roles but constitutes a general procedural framework applicable to any statement with experiential content. In the experimental study, adult participants were presented with truthful and non‑truthful statements crossed with broad vs. specific analytic hypotheses. The study examined how the mode of hypothesis presentation influences the selection of the focal episode, the selection of truth‑indicative cues, and final truth judgments. Specific analytic hypotheses focused participants’ attention on the critical episode and suppressed the influence of non‑critical information, thereby promoting more accurate and selective interpretation of the structural properties of the statements. In contrast, broad analytic hypotheses led participants to interpret the statements in an overly global manner and to rely more heavily on peripheral cues. These findings clearly show that the reliability and consistency of statement analysis are determined less by the type of checklist employed than by procedural factors such as the specificity of the analytic hypothesis, the accuracy of episode setting, and the a priori specification of evaluation criteria. Taken together, the study shifts the focus of statement analysis from checklist‑based scoring to the formulation of episode‑based analytic hypotheses and their testing procedures, thereby demonstrating—across theoretical, case‑based, and experimental levels—that statement analysis can be established as a more rigorous social‑scientific evaluation procedure. Furthermore, by presenting an analytical procedure that is not constrained by the direction of the statement (allegation vs. denial) or by offence type, the study provides empirical grounds for the institutionalization, standardization, and professional training of statement analysis in legal practice.
Subjects: statement analysis, experience‑based analysis, specific analytic hypothesis, Statement Validity Assessment (SVA), Reality Monitoring (RM)