Migration and crime

Migration can be expected to have both a positive and negative effect on crime

Researchers argue that there are several different factors that could contribute to an effect of migration on crime. These include factors that can lead to a direct effect on crime through migrants themselves committing more or less offences than the rest of the population. At the same time, other factors linked to migration may have an indirect effect on crime by influencing levels of involvement in crime in the rest of the population.

Within both groups of factors, there are those that suggest that migration would be expected to increase crime levels and those that instead suggest a reduction in crime as a result of migration. In order to estimate migration’s net effect on crime, knowledge of both the direct and indirect effects is needed, since they can cancel each other out to a varying extent. It is possible, for example, that migration might lead to an increase in crime through direct effects but to a decrease in crime in other parts of the population.

Studies focus on three levels of analysis

The links between migration and crime have primarily been examined at three different levels of analysis: the national level, the area level and the group level.

• Studies at the national level describe either how migration correlates with crime trends in society by using simple comparisons of time series for crime trends and the proportion of migrants in the population, or by comparing crime levels between countries with higher and lower levels of immigration.
• Studies focusing on the area level analyse the link between migration and crime by focusing on variations in crime between different geographical units within the same country, such as municipalities or counties.
• Studies at the group level compare rates of involvement in crime between native-born and foreign-born individuals on the basis of different sources of crime data.

Studies at the national level

Analyses that present simple time series comparisons of crime trends and trends in the proportion of migrants in the population show that there is no simple correlation between migration and crime trends at the national level. Overall crime trends are influenced by many different factors, and the effects of migration are small compared to the combined effect of these other factors, which influence crime among both foreign-born individuals and the larger native-born population.

Studies examining whether crime rates are higher or lower in countries that receive more or fewer migrants show that high-income countries in general have higher rates of registered property crime than low-income countries, and lower homicide rates. The studies also show that these differences are due to factors linked to the countries’ economic and demographic development and not to immigration levels. There is no correlation between different countries’ crime rates and immigration trends when differences in demographic development and GDP per capita are taken into account. At the same time, high-income countries have higher levels of immigration because they tend to constitute the most attractive destinations for international migration.

Studies at the area level

The studies that are considered to have the greatest potential to provide insights into migration’s net effects on crime are those that analyse the links between migration and crime at the level of different areas within the same country. These are the only studies that use a research design that takes into account both the direct and indirect effects of migration, and which can also provide answers about the effects of migration in a particular country.

Area-level studies show that migrants tend to concentrate in certain areas and that these areas often have higher average crime rates and can be considered more criminogenic. When controlling for this, studies from the USA and Europe show a picture that is somewhat difficult to interpret.
In the USA, studies tend to show that migration either has no effect on crime or a weak crime-reduction effect.

There are methodologically robust area-level studies that have examined the link between migration and crime rates in several European countries during various parts of the period from the 1990s onwards. Several European studies report a positive correlation between migration and one or more categories of crime (more migration produces higher crime rates), while at the same time several studies find no significant effect, and some report that migration has a negative effect on crime (with more migration producing lower crime rates).

There are some differences in the main patterns of findings between studies that have analysed very large inflows of, for example, asylum seekers over a relatively short period of time and studies that have examined periods characterised by less extreme migration flows.

Major migration “shocks” often linked to an increase in crime

In several cases, but not always, methodologically robust European studies focusing on very large migration inflows show that this type of migration event can lead to higher rates of both violent and property crime, at least in the short term. Most of these studies have focused on the wave of migration that reached Europe in the mid-2010s as a result of the civil war in Syria. The majority of the studies have been conducted in Germany and show that the increase in violent crime linked to migration only applied to crimes against foreign nationals – the number of victims of violent crime with German citizenship decreased during the years surrounding this wave of migration.

There are some differences between the various studies that are difficult to interpret, but a reasonable conclusion is that the large wave of migration that reached Europe in the mid-2010s led to an increase in the crime rate in countries with a large inflow of asylum seekers in relation to their population size. At the same time, the magnitude of the effect must be considered uncertain (estimates vary between different studies).

The available analyses of Swedish conditions during the period around 2014–2016 indicate an increase in violent crime but show varying results in terms of an effect on property crime. For Sweden, there are no analyses like those from Germany that have examined who was affected by the increase in violent crime.

The results from both the European and Swedish analyses of the wave of asylum seekers only focus on the years around the actual “migration shock”, and there is currently no research on the long-term effects that this wave of migration has had on crime. At the same time, other studies show that research findings on the effect of this type of very large migration flow cannot be generalised to other types of migration or other time periods.

Area-level studies of less extreme migration conditions

With some exceptions, methodologically robust European studies focusing on less extreme migration conditions have shown that migration has either no significant effect on crime rates, or an effect on property crime (in both directions) but not violent crime.

This applies to studies from Germany, Italy, Spain, the United Kingdom and Norway, as well as a couple of studies that have simultaneously examined two or more European countries, during different parts of the period between the latter years of the 20th century and the second half of the 2010s.

Here, too, there are some differences between studies that are difficult to interpret. For example, analyses from the United Kingdom, Italy and Spain show differences in the effect of migration for different migrant groups, which also vary between studies. A study from the United Kingdom found that migration from Eastern Europe led to lower rates of property crime after the EU enlargement in 2004, while a study on Italy and Spain from the same period found that migration from Europe had the opposite effect on property crime in these countries.

The study from the United Kingdom showed that refugee migration from various countries in Africa and the Middle East led to an increase in the rate of property crime but had no effect on violent crime. The study on Italy and Spain, on the other hand, found that migration from both Africa and Central and South America had a negative effect on both property and violent crime (the more migrants from these countries, the lower the crime rate).

The only methodologically robust study from the Nordic countries that does not focus on the effect of the large wave of migration in 2014–2015 analysed the effects of migration on crime in Norway during the period 2007–2016. After controlling for the structural conditions that characterise the areas where migrants typically settle, the results showed that migration had a significant and negative effect on crime for both labour migrants and refugees (the larger the proportion of migrants in the population of an area over time, the fewer crimes per capita).

Studies at the group level

Studies at the group level are mostly descriptive in nature, focusing only on the possible direct effects of migration on crime. As a result, they do not claim to provide a basis for estimating migration’s net effects on crime in society. It is at this level of analysis that most Nordic studies on migration and crime have focused their attention.

The results of this group-level research show that migrants in Western Europe and the Nordic countries exhibit a higher average level of involvement in crime than native-born individuals, whereas in the USA and certain other countries migrants are registered for crime at a lower rate than the native-born population.

Nordic studies that have examined variations in over-representation between different groups of migrants show a generally lower over-representation or an under-representation in crime for people from high-income countries and people who have migrated for reasons of work or education, and a higher over-representation among people from low-income countries and people who have migrated as a result of war and conflict in their country of origin. Research also shows that access to the labour market plays an important role for migrants’ involvement in crime in recipient countries.

Studies from both Sweden and other Nordic countries also show a decline in involvement in crime among both native-born and foreign-born individuals in the period after the 1990s, with the decline being greater among foreign-born individuals. There is a lack of research on the reasons behind this trend.

Assessment

It is no easy task to draw conclusions about migration’s net effects on crime in society at a general level. The research shows that the effect can vary, for example between different migration events, different groups of migrants and different reception contexts.

One result of the research review that is difficult to interpret is the contrast between the similarities between the USA and Europe in the findings from many area-level studies and the differences between the USA and Europe in studies at the group level. Several area-based studies from both continents show no effect of migration on crime, despite clear differences between the USA and Europe in terms of the under- and over-representation of foreign-born individuals in crime.

Given the over-representation of foreign-born individuals in crime in Europe, the finding that migration has a null effect on crime rates would reasonably imply that migration has affected the recipient countries in a way that has led to a reduction in crime among the rest of the population. One possible partial explanation highlighted in the research is that, over time, foreign-born individuals may have replaced native-born individuals in certain criminal markets, which have always existed but are no longer dominated by native-born individuals in the same way as previously. Other possible partial explanations are that in many countries, foreign-born individuals do not constitute a large enough proportion of the population to cause noticeable changes in crime at the area level, or that migration has affected the conditions of the rest of the population in a way that has led to a lower exposure to risk factors for crime over time. For example, there is research from Europe showing that one effect of migration to Western Europe during the 1990s and 2000s was a shift in the native population to more complex and better paid work.

Insufficient research to draw reliable conclusions about Sweden

Unfortunately, it is not possible to draw any conclusions about migration’s net effect on crime in Sweden in the modern era based on the existing research. At present, there is insufficient research in the form of methodologically robust studies that have examined the overall effect of migration to Sweden, taking into account both the effect of the over-representation of foreign-born individuals in crime and migration’s possible effects on crime in the rest of the population.

It is also difficult to generalise to Swedish conditions from European area-level studies. As has been noted, area-level studies show different effects for different groups of migrants in the same country, and the effect of migration from the same country of origin or region may vary between different recipient countries. Migration’s effects on crime may also vary between different reception contexts, which also change over time, not least in terms of labour market conditions. Given that different countries have different migration patterns – and migration patterns within the same country change over time – methodologically robust Swedish studies from different parts of the modern era would be needed in order to be able to draw conclusions about migration’s net effect on crime in Sweden.