Absolute versus relative socioeconomic disadvantage and homicide: a spatial ecological case–control study of US zip codes

Abstract

Background Homicide is a major cause of death and contributes to health disparities in the United States. This burden overwhelmingly affects people from racial and ethnic minority populations as homicide occurs more often in neighborhoods with high proportions of racial and ethnic minority residents. Research has identified that environmental factors contribute to variation in homicide rates between neighborhoods; however, it is not clear why some neighborhoods with high concentrations of racial and ethnic minority residents have high homicide rates while neighborhoods with similar demographic compositions do not. The aim of this study was to assess whether relative socioeconomic disadvantage, (i.e., income inequality), or absolute socioeconomic disadvantage (i.e., income) measured at the ZIP code- and state-levels, is associated with high homicide rates in US ZIP codes, independent of racial and ethnic composition. Methods This ecological case–control study compared median household income and income inequality in 250 ZIP codes with the highest homicide rate in our sample in 2017 (cases) to 250 ZIP codes that did not experience any homicide deaths in 2017 (controls). Cases were matched to controls 1:1 based on demographic composition. Variables were measured at both the ZIP code- and state-levels. Results Lower median household income at the ZIP code-level contributed most substantially to the homicide rate. Income inequality at the state-level, however, was additionally significant when controlling for both ZIP code- and state-level factors. Conclusions Area-based interventions that improve absolute measures of ZIP code socioeconomic disadvantage may reduce gaps in homicide rates.

Inequalities in Violent Death across Income Levels among Young Males and Females in Countries of the Americas

“…The finding of a clear cross-country pro-poor inequality pattern in mortality due to homicide among young males and females—along with its significant gender gap—is also supported by external evidence [ 28 , 29 , 30 , 31 , 32 ], albeit in studies on either general or adult populations. Interestingly, this inequality pattern is found to be mediated by an array of psychosocial factors, such as income inequality [ 28 , 29 , 30 ], interpersonal trust and social capital [ 28 ], social disorganization [ 31 ], institutionalization of social norms [ 32 ], and even climate temperature [ 30 ]. It remains to be explored what particular psychosocial factors and vulnerabilities might be at play among adolescents and young adults in the Americas that could explain the ubiquitous inequality pattern observed elsewhere.…”

US homicide rates increase when resources are scarce and unequally distributed

“…Homicide rates across the US have been trending precipitously upward in the last few years (Lopez, 2022 ). Recent studies seeking to explain variation in homicide rates nominate diverse causes, including ambient temperature (Xu et al, 2020 ), city greenness (Sanciangco et al, 2021 ), firearm ownership (Studdert et al, 2022 ), firearm laws (Crifasi et al, 2018 ), structural racism (Unnever et al, 2021 ), income inequality (Daly, 2016 ), the interaction between absolute income and income inequality (Burraston et al, 2019 ; Gobaud et al, 2022 ), and more. While the homicide rate is clearly driven by multiple factors, many correlational studies lack the systematic theory needed to identify the underlying factors that structure individual motivations which may lead someone to kill another.…”

“…A large amount of empirical research stems from the economics, sociology and political science literature, which has long proposed a positive relationship between various forms of inequality (e.g. ethnic inequality) and violent intergroup conflict (Cederman et al, 2011 ; Horowitz, 1985 ), including homicide (Aransiola et al, 2021 ; Burraston et al, 2019 ; Gobaud et al, 2022 ). Causal arguments are varied, but often propose violence to be a reaction to structurally imposed constraints on material and social capital leading to deprivation in certain communities (e.g.…”

“…Indeed, there is some evolutionary research suggesting ethnic dominance hinders contributions to public goods and may foment inter-ethnic conflict (Waring & Bell, 2013 ). The ‘social disorganisation theory’ suggests that local socio-economic conditions are more important than individual characteristics when explaining criminal activity and propose homicide to be a reaction to the breakdown of social cohesion in disadvantaged communities, which fosters feelings of resentment, frustration, hopelessness and alienation (Blau & Blau, 1982 ; Gobaud et al, 2022 ). These theories certainly differ from evolutionary models in their ultimate explanation of violent behaviour and focus more on the drivers of socially imposed constrains and the proximate phycological mechanisms that facilitate violent acts.…”

“…These theories certainly differ from evolutionary models in their ultimate explanation of violent behaviour and focus more on the drivers of socially imposed constrains and the proximate phycological mechanisms that facilitate violent acts. Nonetheless, they articulate with evolutionary models in positing a causal relationship between resource deprivation and homicidal behaviour (Blume, 2021 ; Burraston et al, 2019 ; Gobaud et al, 2022 ; Vásquez et al, 2023 ).…”