The making of an expert detective: the role of experience in English and Norwegian police officers’ investigative decision-making

ABSTRACT

Biased decision-making in criminal investigations can impede or arrest the progress of justice. Previous research has not systematically addressed the effects of professional experience on the quality of detectives’ decision-making. Using a quasi-experimental design, this study compared the quality of investigative decisions made by experienced detectives and novice police officers in two countries with markedly different models for the development of investigative expertise (England and Norway). Participants (N = 124) were presented with two semi-fictitious cases and were asked to report all relevant investigative hypotheses and necessary investigative actions in each case. The quality of participants’ responses was gauged against a gold standard established by a panel of senior homicide experts. In the English sample, experienced detectives vastly outperformed novice police officers in the number of reported gold-standard investigative hypotheses and actions. In the Norwegian sample, however, experienced detectives did not perform any better than novices. We argue that English (vs. Norwegian) detectives may benefit more from professional experience due to their Professionalising Investigation Programme and a nationwide accreditation program, requiring them to engage in extensive standardized training, systematic evaluation and synchronized development. In contrast, Norway lacks such requirements. Methodological limitations and implications for police training and accreditation policies are discussed.

KEYWORDS:

• Criminal investigation
• homicide
• decision-making
• detective
• expertise
• accreditation

ORCID

Ivar Fahsing http://orcid.org/0000-0002-1395-2612

Karl Ask http://orcid.org/0000-0001-5093-5902

Notes

1. Other, potentially relevant, population differences are more difficult to control for. For instance, differences in population size and crime rates (e.g., homicide rates have been higher in the UK [1.7 per 100,000 population] than in Norway [1.0] over a recent 10-year period; UNODC, 2013) may influence the possibility to gain professional experience; an English SIO may have been exposed to a greater variety of complex murder investigations than a Norwegian detective with the same number of years on the job.

2. A Bachelor's degree in Policing has since 1993 been compulsory for all new Norwegian police officers.