The narrative and the numbers: how does migration affect crime?

Ali Ahmadi, Catherine Barnard and Fiona Costello argue that, contrary to common media narratives, there is no clear link between increased migration and higher crime rates.

The media often associates migrants, particularly asylum seekers and refugees, with criminality. A study of news coverage in Canada, the UK, and the US found recurring negative themes, including describing migrants as ‘rapists and criminals,’ and linking migrants with ‘terrorism’.

But what does evidence say? Are asylum seekers and refugees really more likely to commit crimes? And, if they are, will a government leaflet, setting out the basic rules, deter them?

Research does not show a consistent link between migration and crime. In fact, across OECD countries, an increase in immigration has not seen an increase in the crime rate (particularly property, violent, and drug crime). However, a closer look at the figures reveals significant variation, depending on immigration policies, immigrants’ backgrounds, and the post-arrival conditions. For instance, a study of 128 countries found that while migration was positively associated with crime in countries such as Iran and Ukraine, it was associated with lower crime indices in Egypt, Mauritius and the United States. Similarly, in the UK, the proportion of non-citizens among people convicted or incarcerated is similar to that of the adult population (about 12%), or lower once age is taken into account (non-citizens tend to be younger, and young men are more likely to commit crimes).

Crime rates also vary by nationality and offence type. For instance, Afghans are over-represented in sexual offences and Albanians are over-represented in drug offences (although the available data do not allow for a reliable measurement of this over-representation). More broadly, high-income countries (e.g., China, France) are less represented in convictions and low-income countries (e.g., Afghanistan, Iraq) are over-represented. This can be explained by socio-economic and family circumstances, which is also in line with research within the British population. For example, young adults who had spent time in care were roughly ten times more likely to have been found guilty of an offence than those who had never been in care.

Crime rates also differ according to how people enter a country and their post-arrival conditions. For example, immigrants who come for study and work (generally those with more affluent socio-economic backgrounds) are less likely to commit crime. On the other hand, asylum seekers and refugees are more likely to be convicted or incarcerated. A study in the UK found that the large arrival of asylum seekers in the late 1990s led to a small but statistically significant increase in property crime. Similarly, a study in Germany found a small increase in property and violent crime one year after refugees arrived. This could be explained by the limbo these individuals face in their host countries post-arrival. A prolonged period of uncertainty can create financial and social pressures. In the UK, over 36% (17,668 people) of those claiming asylum wait for more than a year for an initial decision and the average time for an appeal for asylum applicants is 67 weeks. This limbo may, in some cases, increase the risk of involvement in crime.

However, even this increase should be interpreted carefully. Researchers have identified an ‘over-reporting bias,’ where people may report or attribute crimes to refugees more often in areas with large refugee populations because of prejudice, heightened public attention, and/or increased police alertness.

Government policies, particularly rules on employment and legal status, can either increase or reduce crime among asylum seekers. People who cannot work legally have fewer opportunities to earn a legitimate income, which creates financial pressures that may lead to them engaging in illegal activity. For instance, although crime increased among asylum seekers in the UK, no such effect was observed following the arrival of a large number of EU labour migrants after 2004, who had immediate access to employment. Similarly, in Italy, migrants with legal work permits showed a similar or lower propensity for committing crime compared to natives. And those whose status had been legalised were significantly less likely to commit serious crimes in the following year.

Similarly, in Türkiye, which hosts the world’s largest Syrian refugee population, crime rates fell following the arrival of refugees. Researchers suggested that the risk of deportation, combined with humanitarian cash-transfer programmes such as the Emergency Social Safety Net, may have discouraged illegal activity.

A study from Denmark showed that a more expansive integration support such as employment and language training for adult refugees also has significant intergenerational effect in terms of, among other things, lowering juvenile crime.

Recently, the UK government distributed a short guide for asylum seekers covering public behaviour, sex and consent, domestic abuse, and gender equality, and highlighted the legal consequences of non-compliance. We are not aware of any evidence that pamphlets of this kind, on their own, produce a substantial reduction in criminal behaviour. A study of North Korean refugees in South Korea found that greater familiarity with the law was associated with lower offending rates, indicating that legal awareness may have some preventive value. The guide could therefore be beneficial if combined with in-person orientation and ‘psycho-education’ programmes such as anger management and violence prevention, particularly for adolescent and young adult refugees. These could build a better understanding of the law and address wider barriers to integration. This may be particularly important for asylum seekers given that trauma and exposure to conflict significantly increase an individual’s propensity to commit violent crime.

To conclude, the evidence is mixed on whether migration increases or decreases crime. It varies across countries and groups and depends on factors such as migrants’ backgrounds (e.g. socio-economic factors, family, etc.), their route of arrival, their legal status and their access to employment. Also, the propensity for crime among migrant populations is highly responsive to government policies. Policies that restrict employment and leave people in prolonged legal uncertainty can create economic pressures. Conversely, policies that provide access to work, social support and secure legal status may reduce these pressures and see crime risks minimised or even reversed. Therefore, reducing prolonged periods of unemployment and legal uncertainty may help people establish more stable lives and could, in turn, reduce the conditions associated with some forms of offending.

By Ali Ahmadi, Research Associate, University of Cambridge and PhD student at Anglia Ruskin University, Catherine Barnard, Senior Fellow, UK in a Changing Europe & Professor of EU Law and Employment Law, University of Cambridge and Fiona Costello, Assistant Professor, University of Birmingham.