Defensible Space Theory Explained


First published in 1972, the defensible space theory was proposed by Oscar Newman. His work as a city planner and architect proposed ideas that could help to keep neighborhoods safe and prevent crime with this theory.

He focused on public health, social control, and crime prevention as it related to community design.

The 5 Factors Which Make Up a Defensible Space

Newman noted a study in the 1970s which found that residents in a high-rise building experienced more crime than those in smaller buildings. He suggested that a building with more people in it creates a feeling where personal responsibility is reduced because a person feels like they have little or no control over their circumstances.

As he looked at this concept and developed the defensible space theory, he outlined five specific factors that would need to be present to create such a space.

  1. Territory. The home of an individual must be treated as sacred ground.
  2. Surveillance. The physical characteristics of the home must provide a person with an ability to see or know what is going on around them.
  3. Image. The home must be structured in such a way that it can provide real security, or at least the sense of security, when it is occupied.
  4. Milieu. Features of the home must also provide a sense of security, such as its location near a police station, the installation of a security system, or a proximity to a busy commercial area.
  5. Safe Areas. If the primary space of the home is breached, there must be a safe adjoining area that provides higher-level services in the other four key points that can be accessed.

Newman suggests that when a criminal is placed into an isolated position, it becomes easier for homeowners to defend their home space. When responsible parties care for and own their homes, and can watch neighborhoods with regularity, then a criminal feels less secure in taking an action.

In the defensible space theory, environmental design is what can control or mitigate criminal behavior.

Does Defensible Space Theory Work?

Two high-crime areas have experimented with the defensible space theory. In St. Louis, private homes experienced lower crimes than public areas. When people had the capability and incentive to defend their own spaces, then crime went down. St. Louis allowed people to ask unwelcome people to leave their street because they owned it with the city. On a public street, such an action could not occur because there is no ownership, so someone couldn’t be asked to leave until a crime was committed.

Hartford saw very different results. The US Department of Justice closed the streets to a neighborhood, assigned police teams to patrol them, and had new buildings be designed around the idea of limiting access to the city. Their efforts at implementing the defensible space theory showed virtually no reduction in the local crime rate.

How the Defensible Space Theory Is Implemented Today

The influence that Newman had on urban design is still seen in the construction of new homes and buildings. Homes are built in such a way where the resident is able to utilize and control their environment based on their current capabilities. This includes family structure, income level, and socioeconomic background.

Proprietary attitudes are also emphasized in the defensible space theory. When residents can take ownership over a specific tract of land, it gives each person a sense of authority and the confidence to expel a potential intruder.

Interior and exterior spaces are designed to let residents view as much of their surrounding environment as possible. Windows are placed where a sphere of influence can be maintained. That may include a city street, a local park, or an unfenced yard. At the same time, the structure must reduce any visible vulnerabilities that may suggest it is an easier target to someone who may be thinking about committing a crime.

Amenities are also considered within the defensible space theory. By keeping key needs close, such as food, water, and clothing, the time away from home that a person must spend is reduced. That limits the window of opportunity for a criminal to act and naturally reduces crime as a side effect.

Newman included ownership as part of the defensible space theory because people are more willing to defend something of their own than something that they rent. By creating a defensible space that is owned, territory becomes sacred. Monitoring is frequent. This reduces criminal opportunities, which according to the theory, will then reduce the crime rate.