Criminal evidence: examining what works in cutting crime

The explosion in data and evidence about crime should have transformed how governments handle policing and criminal justice, says Tom Gash – but instead, we keep on building policies around myths, stereotypes and preconceptions
Across the world, governments have been investing in improved data and research on patterns of crime and possible causes.
In rich countries, police forces routinely record when and where crimes take place, allowing them to spot patterns and ensure that officers are ready to prevent and respond to trouble. Some forces are using sophisticated software and even machine learning to ensure better predictions, looking at variables like social media activity and locations of school buildings as well as historic crime patterns.
Data and analysis is also changing how governments assess the risks of releasing offenders. These tools are controversial because they are never perfectly accurate and can assess people’s reoffending risks by examining the behaviour of others with similar characteristics, rather than by examining that individual’s track record and carrying out a personal assessment. But such methodologies have helped ensure that those still deemed high-risk at the end of their full sentence are monitored more heavily in the community, under schemes such as the UK’s Multi-Agency Public Protection Arrangement.
Meanwhile, knowledge about what works in reducing crime has been transformed over the past 20-30 years, thanks to a growing community of academics who don’t just theorise about crime, but rigorously evaluate measures aimed at tackling it. USA’s Washington State Institute of Public Policy provides independent advice to the state legislature on which policies will work in particular circumstances, and has synthesised thousands of empirical studies. Their work means that policymakers can relatively quickly assess which interventions tend to reduce reoffending (drug treatment and cognitive behavioural therapy do well); the impact of prison (rather ineffective at reducing crime); and the types of policing that are most effective (random patrols make little difference; hotspot policing does). Of course, what works in one setting won’t always work in another, and the ways in which initiatives are implemented make a big difference to results – but such evidence provides invaluable information on where public money should be invested, and where it can be withdrawn safely.
One of the most consistent findings of recent research is that reducing easy opportunities for crime can have a major impact. My book Criminal: The Truth About Why People Do Bad Things shares how vehicle theft has fallen by more than half in many countries, due to improved security measures such as immobilisers; how alcohol-related violence has plummeted where urban centres have made their night-time environments less violence-inducing; and how metal theft declined dramatically once scrap metal dealers were banned from paying cash for scrap, ensuring that all those selling scrap could be tracked if their goods were later found to have been stolen.
Many successes in crime reduction have little to do with the criminal justice system, relying instead on changes in commercial regulation, technological advances, and the work of other government agencies, local communities, and businesses. Many believe that opportunity-reduction explains a large part of the near-universal falls in crime in advanced democracies since the early 1990s.
More could be achieved, but public and political attachment to certain policies is sucking up scarce resources. Many governments continue to react to high-profile incidents of crime by toughening sentences for everyone, rather than giving judges the discretion to do what is right in the individual case. This has vastly increased the sums spent imprisoning low-risk prisoners in countries such as the US, Australia and the UK. Politicians also keep promising voters more ‘feet on the beat’, including in communities where crime levels are so low that officers have little to do. And the media perpetuates scare stories wrongly arguing that crime is caused by immigration, creating mistrust that prevents communities from working together to tackle local problems.
These unhelpful responses are often popular with those on the political right. But left-wingers are equally culpable of undermining progress. When people argue that nothing can be done about crime until poverty and inequality are addressed, they are arguing against decades of evidence showing that we can make a difference to crime without tackling these (admittedly vast) problems. And they are disproportionately harming the poor, who in every society are most adversely affected by crime.
It is one of the outrages of our time that myths about crime leave us all less protected than we should be, even while taxpayers fund often-bloated criminal justice systems. Countries across the world are learning better ways of doing things, but for the fight against crime to truly deliver results, we first need to replace myth-based approaches with those founded on evidence. Without this shift, urgently-needed investment in agendas such as addressing the explosion in internet-enabled crime will not be as forthcoming as it should be, and we will miss out on countless opportunities to prevent crime instead of responding to it.
Tom Gash is the author of Criminal: The Truth About Why People Do Bad Things (Penguin, 2016). He works internationally as a government adviser and is a Senior Fellow at the Institute for Government and the London School of Economics.