Modeling the Dynamics of Street Robberies

Achieving a better understanding of the crime event in its context remains an important research area in criminology that has major implications for making better policy and developing effective crime prevention strategies. However, progress in this area has been handicapped by a lack of micro-level data and modeling tools that can capture the dynamic interactions of individuals and the context in which they occur. This research creates a conceptual model of street robberies that is based on extant theory and empirical research. Four distinct versions of that conceptual model are implemented using agent-based modeling software (ABMS). All of these versions incorporate core elements of routine activity theory—a motivated offender, suitable target, and a lack of capable guardians. From a research standpoint, this enables specific components of routine activity theory to be explored within a controlled environment. Specifically, the core premise that changes in the social structure have increased crime rates will be examined by varying the time spent away from home over five different temporal experiments. While the original concept of social changes in routine activities did not explicitly consider spatial aspects, this research draws from the geographic literature on activity spaces and offender travel behavior. Inclusion of spatial aspects is accomplished by defining two different types of agent movement—directed and random on two different landscapes – uniform grid and street network. The focus of this study is on operationalizing theory to study the dynamic interactions between individuals from which aggregate crime rates and crime patterns emerge. Research conducted using simulation offers a cost-effective supplement to field research. When used in concert, the two methods focus investments in research by identifying strategies that simulation indicates are promising for further research via field experiments. Research conducted with simulation software offers the ability to examine a variety of policy questions related to crime prevention, policing strategies, and the best response to terrorist incidents. In the area of crime prevention, expensive policies suggested by Crime Prevention Through Environmental Design (CPTED) literature could be tested before investments in physical changes are made. Exploration of the components of the decision to offend (victim selection, guardianship, site characteristics, etc.) will suggest concrete policy direction to prevent crime. Different policing strategies can be tested (e.g., hot spots policing) to examine the rate and size of the resulting diffusion. Finally, simulation can be used to model the reactions of people during catastrophic events. The model developed here provides the foundation for additional, more richly specified models to be developed.