I help people use data to reduce crime. Associate Professor at @UCLCrimeScience. Former police officer.
Nottingham and London, UK
Joined April 2009
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Hard-drug use (as estimated from metabolic byproducts in sewage) in 🏴 is largely unchanged in 2026, with cocaine, ketamine, heroin and amphetamine being most common. Unlike the US, fentanyl still hasn’t really made an appearance on the UK drugs scene.
gov.uk/government/publicatio…
I wasn’t expecting walking down the middle of the newly pedestrianised Oxford Street to feel so lovely (never a word I’ve used for Oxford St before!). It instantly feels like something that should have been done years ago.
Well done, @MayorofLondon, for finally getting it done.
ALT The section of Oxford Street in central London that has just been pedestrianised. There are crowds of people walking across the full width of the street. Christmas decorations are already hanging across the street.
A quasi-experiment (🇺🇸) found two publicity campaigns (geo-targeted messages broadcast to mobile phones and anti-violence messages stencilled on pavements) had no effect on violent crime.
doi.org/10.1111/1745-9133.70…
Changing the standard for judging police deadly force (🇺🇸) from “reasonable” to “necessary in defense of human life” had no effect on how many people were killed by police (as proponents claimed) or on how many officers were injured (as opponents claimed)
doi.org/10.21428/cb6ab371.1b…
Liberating criminology from a narrow focus on offender motivation meant criminologists could also understand that crime is partly caused by opportunities, which has been hugely important in developing effective ways to prevent crime.
doi.org/10.1111/1745-9133.70…
Matt Ashby retweeted
"The UK has fallen because two years ago someone who had probably never handled a gun before was photographed holding an empty gun the wrong way"
Is such a lame outrage chasing pile of tepid nonsense, you'd think the world had run out of things to be upset about.
This experiment finds a practitioner or global-south researcher without expensive institutional journal subscriptions can only access about 5% of criminology research.
Long past time more researchers (especially in the US) got serious about open access.
doi.org/10.21428/cb6ab371.bc…
Useful short summary by @PizaEric of research evidence on the limited effect of CCTV (including automated numberplate recognition cameras) on crime and police outcomes.
counciloncj.org/wp-content/u…
The decision not to install immobilisers on Kia/Hyundai cars (🇺🇸) led to over 1.1 million extra vehicle thefts over 5 years.
Note: unlike other developed countries, the US doesn't require manufacturers to fit cars with immobilisers.
crimrxiv.com/pub/4u5hwcwg/re…
When a temporary speed trap (🇦🇺) appears on phone navigation apps (Waze, Google Maps, etc.), average vehicle speed on that road drops by about 4km/h.
One for academics still teaching students that offenders don't make rational choices, I guess. 😉
doi.org/10.1007/s11292-026-0…
Matt Ashby retweeted
I’ve heard Journal of Quantitative Criminology will soon require opens data/code…which will make it the only journal in the entire field to do so. In late 2026.
We should be embarrassed! Complete abrogation of basic scientific responsibility for decades. And seemingly no urgency from the editors of Criminology, Justice Quarterly, Criminology & Public Policy, or Journal of Experimental Criminology.
There was an effort to get there from the last two editors of criminology, but the new editors haven’t followed through.
Meanwhile, what year do you think the first preregistered RCT was published in the fields flagship journal Criminology? If you guessed 2026 then you win (proud to have authored that one 😁).
Chatting with a friend about ongoing efforts in Economics to use AI to replicate every econ paper ever published. This is scary for individual researchers, of course (everyone lives in fear of a coding error), but clearly good for science.
I'd love to see this applied to Criminology, but those journals still don't require authors to post their data or code. 🙄
Embedding mental-health clinicians in police control rooms (🇺🇸) was associated with a small drop (about 7%) in police deployments to mental-health calls. Seems like this would have been a good opportunity for a randomised controlled trial, though.
doi.org/10.1080/0735648X.202…
Repeat victimisation happens to police officers, too, especially when it comes to violent crime. A useful reminder in @PolicingInsight of the importance of leveraging concentrations of victimisation risk when trying to prevent officers being assaulted.
policinginsight.com/feature/…
Of 812 articles in the British Journal of Criminology (2014–2024), only 0.2% (two articles in 11 years!) used experimental/quasi-experimental methods.
(Quasi-)experiments aren't good for everything, but is UK crim research really using the right methods?
doi.org/10.1007/s11292-026-0…
ALT Dumbbell chart comparing the percentage of articles using quasi-experimental (QE, red) and Big Five (dark blue) research designs across 15 criminology journals. Big Five percentages are higher in almost every journal. The largest difference is in the Journal of Experimental Criminology (34% Big Five versus 9% QE), followed by the Journal of Quantitative Criminology (10% versus 7%) and Criminology and Public Policy (8% versus 5%). In most other journals, both percentages are below 5%, with differences generally under 3 percentage points. The British Journal of Criminology and Legal and Criminological Psychology have approximately 0% for both categories.
Mark Rowley hits the nail on the head:
“If we're serious about policing London effectively … Why wouldn't we want people who understand and can connect with every part of one of the world's most globally connected cities?”
lnkd.in/p/e9XTGmvU
Replacing sodium street lights with LEDs (🇺🇸) led to substantial reductions in night-time property and violent crime outdoors, but the effect only lasted for six months before crime reverted to previous levels.
doi.org/10.1007/s10940-026-0…
A randomised trial (🇺🇸) of sending police drones to calls at the same time as dispatching officers found the drones decreased both how quickly police arrived at calls and how quickly calls were resolved.
(Not yet peer reviewed)
doi.org/10.21428/cb6ab371.97…
An excellent blog post on some of the challenges of using generative AI tools in policing. As so often, it’s the non-technical issues that are the hardest to work through!
Definitely worth your time:
stephenrussell996702.substac…
Incorporating street networks into geographic profiles of serial homicides produced results that were no more accurate, despite profiles using street networks requiring more work and taking longer.
doi.org/10.21428/cb6ab371.c0…
