Defensible space theory

The defensible space theory of architect and city planner Oscar Newman encompasses ideas about crime prevention and neighborhood safety. The theory developed in the early 1970s, and he wrote his first book on the topic, Defensible Space in 1972. The book contains a study from New York that pointed out that higher crime rate existed in high-rise apartment buildings than in lower housing projects. This, he concluded, was because residents felt no control or personal responsibility for an area occupied by so many people. Throughout his study, Newman focused on explaining his ideas on social control, crime prevention, and public health in relation to community design.

As defined in Newman's book Design Guidelines for Creating Defensible Space, defensible space is "a residential environment whose physical characteristics—building layout and site plan—function to allow inhabitants themselves to become key agents in ensuring their security." He goes on to explain that a housing development is only defensible if residents intend to adopt this role, which is defined by good design: "Defensible space therefore is a sociophysical phenomenon," says Newman. Both society and physical elements are parts of a successful defensible space.

The theory argues that an area is safer when people feel a sense of ownership and responsibility for that piece of a community. Newman asserts that "the criminal is isolated because his turf is removed" when each space in an area is owned and cared for by a responsible party. If an intruder can sense a watchful community, he feels less secure committing his crime. The idea is that crime and delinquency can be controlled and mitigated through environmental design.

There are five factors that make a defensible space:

The concept of defensible space is controversial. A United States Department of Justice experiment in Hartford, Connecticut closed streets and assigned police teams to certain neighborhoods. New public housing projects were designed around ideas of limited access to the city, but Hartford did not show any dramatic drop in crime. Yet, the private places of St. Louis do have much lower crime than public streets. The reason appears to be that in St. Louis, people had the capacity and incentives to defend their defensible spaces. Residents had the right to ask an unwelcome individual (i.e. not a resident or guest) to leave their street, because they jointly owned it. On public streets, one cannot legally act against someone until they have committed a crime.

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