A different perspective on the forensic science crisis.

Recurrent mentions of a forensic science crisis are reported in the literature. Some 15 years ago, the discussion was focused on the backlog problem. Other issues have been regularly debated since then, including the risk of error, need for independence, importance and risk of contextualisation, increasing fragmentation into separate processes and specialisations. Proposed solutions to solve one problem often led to other issues in other parts of the process. This paper attempts to address the apparent crisis using a different perspective, through a comparison with established disciplines, namely material science, medicine and historical science. The comparison with material science shows that, despite the varied organisational and legal models and the interdisciplinary nature of the field, a common element to all forensic science endeavours exists: the trace. A greater focus on the trace might thus help the development of a holistic approach in forensic science. The comparison with medicine demonstrates that, through the overall process, the main risk shifts from the risk to overlook important hypotheses or traces at the beginning of the process (e.g. problems in the detection of traces/symptoms and formulation of hypotheses) to the risk of supporting the wrong hypothesis at the end of the process (e.g. erroneous test of the hypotheses/diagnostic). Further, in medicine, symptoms are rarely evaluated in isolation, while traces are often evaluated separately. By analogy, epidemiology illustrates forensic science's critical role in preventing crime through forensic intelligence, supporting a more extensive and more collaborative application of forensic science in security issues. The comparison with historical science also indicates that a single trace (i.e. the observed effect) is rarely sufficient to reason on its cause. Retrodiction (abduction) is proposed as an alternative reasoning approach to reconstruct events from the past based on signs uncovered in the present. Finally, the impact of science in investigating crimes is presented as an evolving process. A new trace or information can bring an entirely different light on the reconstruction of past events or prevention of future issues. Thus, issues or challenges in the first stages of the process (i.e., crime scene investigation) should be addressed in priority for subsequent stages to function correctly.