Urdal & Hoelscher: Urban Youth Bulges and Social Disorder Machunovich 2000: 236). Specifically, social or economic marginalization might prevent the accumulation of human capital and wealth and increase competition for employment, thereby reducing the ‘alternative cost’ to engaging in violence (Collier, 2000; Collier & Hoeffler, 2000). Where some form of benefit exists that exceeds expected costs of participating, the risk of disturbance and violence increases. While low-intensity social disturbance events may offer relatively small economic benefits, they might involve rents like looting, protection money and ransoms. On the other side, the cost of participation may also be quite small.

Another strain of the literature focuses on how youth bulges may provide motives for political violence. Large youth cohorts have been argued to be particularly likely to provide motivation for violence if they face unemployment, expansions in higher education with limited employment opportunities, lack of political openness, and crowding in urban centers (Moller, 1968; Choucri, 1974; Braungart, 1984; Huntington 1996; Goldstone, 1991; 2001; Cincotta et al., 2003). Hence, youth engage in violence as a means to redress economic, political or social inequalities and perceived grievances. Homer-Dixon (1999: 157) claims that ‘young urban populations, especially unemployed young men, are easier to mobilize for radical political ends; and young populations generate enormous demands for the provision of social resources like education and jobs’. Further, in urban areas where young men have lost touch with their families and rural support networks, gangs or armed groups may offer camaraderie and support as an alternative to a family unit (Stavrou et al., 2000).

Previously, Fearon & Laitin (2003) and Collier & Hoeffler (2004) have not found any support for the youth bulge hypothesis in cross-national studies of civil war, while Esty et al. (1998) found a statistical relationship between youth bulges and ethnic conflict, and Urdal (2006; 2008) reports statistically significant effects of youth bulges on low-intensity political violence. Hoelscher (2008), in what may be the first city-level time-series study of urban insecurity, finds that national-level youth bulges are statistically associated with higher homicide rates in cities. While we do not propose that young urban age structures necessarily lead to increased disturbance and violence, forms of exclusion that may pertain especially to large youth cohorts, such as depressing effects on young male employment rates and wages (see e.g. Korenman & Neumark, 1997; Machunovich, 2003) are not necessarily well captured by existing data sources. Hence, assuming that large urban youth cohorts are more likely to experience economic and social exclusion, we propose that generally: H1: Large urban youth bulges are associated with higher levels of urban social disorder.

# **2.1 Economic exclusion and unemployment**

When overurbanization combines with underdevelopment, and where job creation and economic growth can’t keep up with urban growth, violence and instability may arguably arise (Goldstone, 2002: 10). Youth unemployment is a significant problem in much of the developing world. The inability to find gainful employment limits young people’s income and skill development. Early age unemployment can negatively affect future earnings and increase the likelihood of later joblessness (e.g. see ILO, 1998, 2004; Mroz & Savage, 2001). Further it appears that urban youth often face far higher unemployment than the general population. This is particularly evident in Sub Saharan Africa, where, for example, Ethiopia’s urban youth unemployment is 37.5% compared with the overall 8.1% unemployment rate (Brewer, 2004: 4). Similarly, 56.8% 4