Measuring the Impact of Cognitive Bias

Measuring the Impact of Cognitive Bias in Fire Investigation

Paul Bieber, CFEI, B.S., M.L.S.
Director of the Arson Research Project, USA

Presented at the International Symposium on Fire Investigation Science and Technology, 2012


Cognitive bias has been found to shape decision making in a wide variety of fields. Criminal investigation and the forensic sciences are no exception.  Fire investigation, part criminal investigation, part forensic examination, is uniquely positioned to be influenced by the affects of cognitive bias.

The 2009 report from the National Academy of Science, Strengthening Forensic Science in the United States; A Path Forward (NAS Report) , recognizes conceptual bias as a factor in all forensic disciplines.  The National Fire Protection Association Guide for Fire and Explosion Investigation (NFPA 921)  acknowledges these biases as a concern in fire investigation.3

This report will explore the most common forms of cognitive bias found in the field of fire investigation, review past research and give recommendations on how these biases might be minimized. It will also present the results of new research which sought to measure the influence of expectation and role bias in fire investigation. A companion report, “Case Study Review of Contextual Bias in Fire Investigation” is available at

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