|Research Digest: Violent Crime
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Income Inequality and Violent Crime
- The relationship between inequality and homicide has been found in many different settings-among developed and developing countries, both between and within countries. Relationships between inequality and violence are stronger when comparing whole societies and tend to be weaker when looking at small areas .
- Several studies have found that small reductions in income inequality cause large reductions in homicide.
- Inequality affects homicide, whereas a society’s average income level does not.
- The relationship between inequality and homicide seems to be part of a more general divisive effect of inequality which weakens the social fabric.
- Almost two-thirds of the higher homicide rates in southern (as compared to northern) states of the United Statesare attributable to their greater income inequality. There are lower rates of homicide in the Canadian provinces than in the states of the USAas a result of their smaller income differences .
As early as 1993 an analysis of 34 studies of violent crime concluded that there was a robust tendency for rates of violence to be higher in more unequal societies .
In 1997, Messner and Rosenfeld  said “A finding that has emerged with remarkable consistency is that high rates of homicide tend to accompany high levels of inequality in the distribution of income.”
Two years later in a study of 50 countries, Lee and Bankston  concluded that “…economic inequality is positively and significantly related to rates of homicide despite an extensive list of conceptually relevant controls.”
Since then the evidence that violence is higher in countries with bigger income differences between rich and poor has not only continued to accumulate, but has also continued to be ignored by governments.
Contrasting trends: England and Wales, and Japan
Englandand Walesexperienced dramatic increases in inequality during the last quarter of the 20th century, particularly during the later 1980s. In contrast, Japanbecame a much more equal society during the second half of the 20th century. Homicide rates in Englandand Walesdoubled between 1967 and 2001, but in Japanhomicide rates fell by 70 percent during the second half of the 20th century. In Englandand Walesthe increase occurred mainly among young working-aged men from poor areas. In Japanthe decline in violence was particularly large amongst young men .
Murder in Britain
On average there are 1.8 murders per day in Britain. The increases in murder over recent decades are predominantly murders of poorer men. Richer areas have experienced opposite trends of low and declining murder rates. Men are twice as likely to be murdered as women. The murder rate amongst young men in their 20s has doubled.
Shaw, Turnstall and Dorling  note that the increase in murder inBritain occurred alongside the dramatic increases in inequality and relative poverty of the 1980s and 1990s. They suggest that “…when people are made to feel worthless then there are more fights, more brawls, more scuffles, more bottles smashed and more knives brandished, and more young men die. The lives of young men have polarised and this inequality has curtailed opportunities; hopelessness appears to have bred fear, violence and murder.”
Small changes in inequality, big impacts on violence
Using data for 39 countries covering the period 1965-1994, Fajnzylber, Lederman and Loayza  show that a small permanent decrease in inequality-such as reducing inequality from the level found in Spain to that in Canada-would reduce homicides by 20%. They also showed that a similarly small decrease in inequality would result in a 23.2% long-term reduction in robberies. The analyses took account of the possible influence of economic development, education, economic opportunities, and urbanisation. The research controlled for causality, so that results would not be affected if there was a feedback loop between income and homicide. Daly, Wilson and Vasdev  found a decrease in income inequality of 0.01 (Gini) leads to 12.7 fewer homicides per 100,000 individuals.
While the vast majority of research in this field supports this analysis, the evidence has a few detractors. Neumayer  questions the link between inequality and violent crime. He recognises that this relationship is widely accepted amongst academics and international agencies, including at the World Health Organisation and World Bank. But, using the UN World Income Inequality Database he suggests that there is no link between income inequality and robbery. He argues that this is evidence for ‘country-specific effects’ influencing inequality and crime. However, such effects were taken into account by Fajnzylber et al.  as well as by Daly et al. . Another explanation of Neumeyer’s findings might be that he looks at robbery rather than homicide and they may have different relationships to inequality. In addition, robbery data is well known to be less reliable than homicide data, especially for international comparisons.
It’s not culture
One of the benefits of cross-national work is that it can reveal patterns that persist despite cultural variations. On the basis of their international analyses, Elgar and Aitken  state that “…inequality relates to homicide independently of local context.” They point out that “[the] large differences in homicide rates between countries with low inequality (such asJapan andDenmark) and countries with high inequality (South Africa and theDominican Republic) are difficult to attribute to geographic proximity or to cultural, political or historical similarities.”
It’s inequality, not income
Daly, Wilson and Vasdev  found that income inequality, but not median income levels, relate to homicide rates. In other words, it is not the level of wealth, but the distribution of wealth, that influences murder and manslaughter. Their research compared Canadian provinces over the period 1981-1996 before going on to look at Canadian Provinces and US states together (see graph below). The more unequal have homicide rates ten times as high as the most equal. After taking account of the effect of income inequality, homicide was not related to average income levels. In this research, single events specific to one province that might influence the pattern are controlled for in order to see the link between inequality and crime more clearly. The authors suggest that this link is caused by inequality stimulating social competition, thus encouraging violence.
Figure 1: Homicide and income inequality in theUSAandCanada
How inequality causes violence
Economic inequality affects crime via psychosocial processes influencing social interactions, cultural norms, values and behaviour. These may be affected by inequality through social status, social support, community cohesion, self-esteem, sense of control over one’s life, loneliness, tension, anxiety, trust, and depression. Elgar and Aitken  consider how greater income inequality leads to more homicides. Across 33 countries lower levels of trust seemed to provide the statistical link which leads from higher inequality to higher homicide. The link was not explained by any tendency for more equal societies to spend more on health and education. They concluded that “Societies with large income differences and low levels of trust may lack the social capacity to inhibit violence and create safe communities.” This has parallels in a study showing that weakening trust and social cohesion may also explain why greater inequality is associated with poorer health . This is echoed by Gilligan who, as a prison psychiatrist, talked frequently to violent men. He argues that inequality makes people more sensitive to experiences of inferiority such as disrespect, loss of face and humiliation which are amongst the most common triggers to violence .
There is near consensus within academia concerning the link between inequality and violent crime. Indeed, as seemingly small reductions in income inequality can lead to sizeable falls in violent crime, these findings have powerful policy implications. The uncertainty surrounding the transmission mechanisms are an additional reason to target economic inequality directly. As Elgar and Aitken  suggest, “…crime reduction policies that ignore income inequality relinquish much of their potential impact on reducing homicide.”
 Hsieh Ching-Chiu, andPugh,MD.(1993) “Poverty, income inequality, and violent crime: a meta-analysis of recent aggregate data studies.” Criminal Justice Review. 18: pp.182-202
 Daly, Martin; Wilson, Margo and Vasdev, Shawn. (2001) “Income Inequality and Homicide Rates inCanadaand theUnited States” Canadian Journal of Criminology 43: pp.219-36
 Messner, Steven and Rosenfeld. (1997) “Political Restraint of the Market and levels of Criminal Homicide: A Cross-National Application of Institutional-Anomie Theory.” Social Forces. 75: pp.1393-1416
 Lee, MR and Bankston, William. (1999) “Political Structure, Economic Inequality and Homicide: A Cross-national Analysis.” Deviant Behaviour. 19: pp.27-55
 Johnson, DT. (2008) “The Homicide Drop in PostwarJapan.” Homicide Studies. 12: pp.146-160.
 Shaw, Mary; Tunstall, Helena and Dorling, Danny. (2005) “Increasing inequalities in risk of murder inBritain: Trends in the demographic and spatial distribution of murder, 1981-2000.” Health and Place. 11: pp.45-54. Available at http://sasi.group.shef.ac.uk/publications/2005/shaw_tunstall_dorl ing_murder_corrected.pdf
 Fajnzylber, Pablo; Lederman, Daniel and Loayza, Norman. (2002) “Inequality and Violent Crime” Journal of Law and Economics 45: pp.1-39
 Neumayer, Eric. (2005) “Inequality and violent crime: evidence from data on robbery and violent theft.” Journal of Peace Research. 42: pp.101-112
 Elgar, Frank J and Aitken, Nicole. (2010) “Income inequality, trust and homicide in 33 countries.” European Journal of Public Health. pp.1-6 Available at: http://www.ncbi.nlm.nih.gov/pubmed/20525751
 Kawachi, I; Kennedy, BP; Lochner, K; and Prothrow-Stith, D. (1997) “Social capital, income inequality and mortality.” American Journal of Public Health 87: 1491-8
 Gilligan, J. (2001) Preventing Violence. Thames andHudson:London
Suggested Citation: The Equality Trust. “Income inequality and violent crime.” Equality Trust Research Digest 2011; no.1:pp.1-5