Both in the industrialized and developing countries, the problems cities face, such as the scarcity of decent housing, unemployment, poor education and inadequate skill levels, poor public transportation, marginalization of neighbourhoods and conflicts from migration, provide a breeding ground for crime and insecurity. National bodies, such as the Australian Commission on Violence, have indicated the culture of violence and gender inequality as possible causes of urban criminality. Economic recession and substance abuse are also probable causal factors. Easily transportable and saleable electronic products and even more cars contribute to the ease with which crime can be committed. Private space makes crime less visible and so more likely. Handguns make crime more deadly.

With the important exception of some affluent Asian cities, such as Hong Kong or Singapore, these problems are generally more extreme in developing countries and exacerbated by the lack of resources, the disproportionate numbers of young persons and the rapid growth in population.

These problems are neither inexorable conditions of cities nor unique to them. For instance, the stable populations and strong family ties found in the large Japanese cities are probably one of the major reasons for their generally low crime rates. The highest crime rates in Canada are found in small northern communities where family and cultural breakdown have reached extremes.

In the affluent post-industrial countries, longitudinal studies have provided a better understanding of the role of the family, schools and neighbourhoods in the development of crime and the relationship between these factors and poverty. These studies follow scientifically the development of a representative sample of persons from childhood to adulthood. The results show that a large proportion of offences (between 50 per cent and 70 per cent, depending on the study) are committed by fewer than 10 per cent of offenders, and that the seriousness of the offences increases the deeper the offender becomes involved in a life of crime. Young people are most likely to become criminally involved during the period between the onset of adolescence and their early twenties. Indeed, research has shown that the younger an individual is when he or she becomes involved in criminal activity, the higher the risk of recidivism.