2026/06/11 by Natascha de Leeuw, J.J. van der Kemp, Stijn Ruiter +1 · 1 voice
Social Sciences · Psychology · #Policing Practices and Perceptions #Crime Patterns and Interventions #Deception detection and forensic psychology
paper · doi:10.1108/pijpsm-12-2025-0261
openalex publication_date 2026/06/11 · openalex created_date 2026/06/12 · openalex updated_date 2026/07/15
Purpose This systematic review aims to provide a comprehensive understanding of the relationship between investigative effort (IE) and case outcomes in criminal investigations. While previous work has highlighted the link between IE and case outcomes, the evidentiary strength of this relationship has not been systematically mapped. We examine the empirical evidence on how IE relates to case outcome and map the proposed underlying mechanisms. Design/methodology/approach This review follows Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines to ensure a transparent approach to the selection and analysis of relevant studies. In total, 38 empirical studies, examining at least one form of IE in relation to case outcomes on case level, were systematically coded to answer the research questions. Findings We identified over 60 forms of IE studied in relation to five different case outcomes. Although many studies report a positive association, the operationalization of IE varies greatly, making it difficult to compare findings. Few studies employ rigorous designs, limiting the ability to draw firm conclusions about causality. Mechanisms explaining the relationship are mentioned but remain underexplored. Originality/value This review fills a gap in the literature by systematically assessing the evidence base of the relationship between IE and case outcome, as well as the underlying mechanisms. It highlights the need for more rigorous research designs and explicit testing of proposed mechanisms. These insights could inform policing practices and guide future research aimed at improving criminal investigations.