Jason Roach and the Art of Catching Criminals by Their Small Mistakes

Some academics influence policing by building institutions; some by running experiments. Jason Roach’s influence is of a rarer kind: he gave officers a genuinely new way of looking at things they were already seeing. The disabled bay parker. The driver who turns out to be disqualified. The small, irritating infractions that fill an officer’s shift and have always been treated as the job’s background noise. Roach’s work reframed that noise as signal — the place where serious offenders quietly give themselves away — and in doing so handed the service one of the few detection ideas that costs almost nothing to use.

The analyst who went looking for the theory

Roach is Professor of Psychology and Policing at the University of Huddersfield, where since 2021 he has directed the university’s Secure Societies Institute. The route there was not the standard academic one. Before the professorship came a spell as a crime analyst at the Home Office and years working in mental health services in the north of England — jobs that involved staring at real offending and real offenders rather than theorising about them. Like the other figures in this series, from Alex Murray to Susanne Knabe-Nicol, his credibility with practitioners rests on having been close to the work itself.

The academic apparatus came to match the practical grounding. He is a Chartered Psychologist and Editor-in-Chief of The Police Journal, one of the longest-established practitioner-facing policing journals; a Visiting Professor at the Open University’s Centre for Policing Research and Learning; and the author of a string of books written, unusually, to be read by the people they are about.

Self-selection policing: the big idea

The work Roach is best known for began with a deceptively simple Home Office finding. In 1999, Sylvia Chenery, Chris Henshaw and Ken Pease published Illegal Parking in Disabled Bays: A Means of Offender Targeting — a Huddersfield study showing that cars parked illegally in disabled bays were disproportionately registered to people of active police interest, around one in four of them. The most committed criminals, the authors reasoned, are also the most versatile: people unwilling to be bound by any rule, including the small ones.

Roach took that observation and, with Ken Pease, built it into a theory and a practice: self-selection policing, set out fully in Self-Selection Policing: Theory, Research and Practice (Palgrave Macmillan, 2016). The premise has become one of criminology’s most quotable lines — “those who do big bad things also do little bad things” — and the practice it generates is described at length in this site’s explainer on self-selection policing: identify the minor “trigger offences” that statistically flag serious offenders, and treat each one as an invitation to look closer. His own study of disqualified drivers in Policing: A Journal of Policy and Practice supplied some of the strongest evidence — an overwhelming proportion of those caught driving while banned had records of other, often serious, offending.

What makes the idea characteristically Roach is its psychology. Self-selection policing is, at bottom, a claim about offender decision-making: that the disposition to break rules is general, not compartmentalised, and that it leaks into observable, minor behaviour. The offender’s own choices do the targeting. No profiling, no guesswork — conduct, not character.

The wider portfolio: how offenders and detectives think

Self-selection is the headline, but the through-line of Roach’s research is broader: a practical psychology of crime and policing, applied wherever decisions get made under pressure. His published work spans investigative decision-making, cold-case homicide reviews, child homicide investigation, terrorism, crime prevention and police wellbeing — the common thread being how offenders, victims and investigators actually think, rather than how procedure assumes they think.

With Pease he wrote Evolution and Crime (Routledge, 2013), asking what an evolutionary lens adds to understanding offending. In Practical Psychology for Policing (Policy Press, 2023) he distilled the discipline into the version a working officer can use — the title is a mission statement. And he carries the translation habit further than most professors will: he writes the long-running Stopping Crime blog at Psychology Today, putting the research case to a general audience in plain English.

The influence, in proportion

The honest accounting, as ever in this series. Self-selection policing has not been adopted wholesale by British forces; Roach himself has restated the case precisely because implementation lags the evidence, and his disqualified-driver paper is candid that organisational obstacles stand between the idea and routine practice. SSP remains a tactic with strong supporting research and patchy uptake — a familiar gap to readers of this site’s Sherman and Murray profiles.

But the durable contribution is secure, and it is twofold. First, a genuinely original detection idea — cheap, fair, evidence-based and conceptually elegant — that any force could pick up tomorrow, and that this site has argued applies inside policing too, to the officers whose small transgressions foreshadow large ones. Second, a model of what a policing academic can be: close enough to practice to be trusted, rigorous enough to be cited, and committed — through the journal he edits, the books he writes and the blog he keeps — to the unfashionable work of making research land where it matters, on shift.

The detective’s craft has always prized the small tell. Roach’s career has been spent proving the tell is real, measuring it, and teaching a sceptical service to use it.

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Sources and further reading

• University of Huddersfield Research Portal, Professor Jason Roach.
• University of Huddersfield, “Professor Jason Roach to lead University’s Secure Societies Institute”, November 2021.
• Psychology Today, Jason Roach Ph.D. — contributor profile and the Stopping Crime blog.
• Jason Roach and Ken Pease, Self-Selection Policing: Theory, Research and Practice, Palgrave Macmillan, 2016.
• Jason Roach, “Self-selection Policing and the Disqualified Driver”, Policing: A Journal of Policy and Practice, 13(3).
• Sylvia Chenery, Chris Henshaw and Ken Pease, Illegal Parking in Disabled Bays: A Means of Offender Targeting, Home Office, 1999.
• Jason Roach and Ken Pease, Evolution and Crime, Routledge, 2013.
• Jason Roach, Practical Psychology for Policing, Policy Press, 2023.
• Open University Centre for Policing Research and Learning, “Professor Jason Roach joins the Centre as a Visiting Professor”.