Melissa Remy

Ocsar Newman's Theory of Defensible Space

Oscar Newman developed his theory of Defensible Space in the early 1970's. His theoretical construct consisted of the interaction between individuals and the environment as a means of making their living environment "defensible space." By creating a sense of community and through the use of such measures as resident surveillance and image, Newman developed ways of combating crime within a residential area, specifically that of high rise apartment buildings. I will begin my paper with an introduction into the history surrounding the construction of defensible space as a theory; including other major theoretical academicians who influenced his work and their theories. I will then discuss Newman's theory and the impact it had on the world of crime prevention. The criticisms of Newman's theory will be discussed, as well as any alterations that were subsequently made as a result. I will conclude by discussing the current usage and popularity of Newman's theory of defensible space.

HISTORY

Oscar Newman's, theory of Defensible Space was created out of a social control model, as well as a model of crime prevention and social ecology. In 1972, Newman, an architect, published Defensible Space, in which his study on crime rates in low-cost housing projects in New York revealed that high-rise apartment buildings had a much higher rate of crime than did those in which there were only three or five story buildings in comparable social settings. His theory had a large impact on future theories and theorists, but the precipitating factors of how and why Newman's theory came to be will be discussed in this project. I will discuss the various historical, social, and political environments relating to each of the models that Newman uses to define his theory: social control, crime prevention as a public health model, and more specifically, crime prevention through environmental design.

SOCIAL CONTROL

The social control model of explanation is historically rooted in the movement of our society from one that was decentralized to centralized, from kinship and tribe to nation state, from custom to law, from informal to formal, and from status to contract. Once the tribal system disintegrated, it was replaced with the agricultural and industrial revolutions, and marked population growth. Within this historical setting, it became necessary for social control to occur (Jeffery, 1990). The model of social control employed by Newman in his theory is one in which control is based on the exchange of goods and services involving pain and pleasure. This exchange model is based on the utilitarian and self-seeking persons concepts who wish to maximize pleasure and minimize pain as seen in the works of Bantam, Beccaria, Mill, and other utilitarians (Jeffery, 1990). Skinnerian based social psychological theories of reinforcement and punishment are also influential in this model of social control (Jeffery, 1990). In order to protect the life, liberty and property we hold so dear, Locke states that we join the state in an attempt to protect these, while submitting ourselves to social control. It is necessary for the survival of human beings that cooperation be present. The evolution of man depended on conflict as well as cooperation. The two of these concepts go hand in hand with each other. The role of cooperation and mutual aid has been noted by many theorists as particularly aiding in our growth, survival, and development as a species. (Jeffery, 1990) So, historically it has been noted that to increase our chances of survival, while competition is inevitable, particularly at the individual level, a method of cooperation must be established between individuals as well.

CRIME PREVENTION

Crime prevention as a tool emphasized the possibility of the use of measures, prior to action, that may reduce the possibility of a crime from occurring. The efforts are directed both at the individual level, and at the environment in which crime occurs. Crime prevention as a method rejects the notions of rehabilitation, incarceration, and retribution. These efforts all focus on an after the fact method of crime control, and are very reactive to say the least, rather than acting in a proactive fashion. In the 1961 work, The Death and Life of Great American Cities, Jane Jacobs was the first to propose a new way of looking at the relationship between the physical environment and crime. Her work was an attack on the urban planning practices of the 1950s, such as the urban renewal and slum clearance practices which she saw as unnecessarily destroying a number of the older urban neighborhoods (Jacobs, 1961). She argued that these older structures provided a number of natural security techniques that could be useful for the community. Among these she mentioned that the structures were close to the street, with stoops, porches, and street level windows, the members of the community used such structures, and through these a sense of community and bonding was established. The removal of such structures would decrease the social interaction, the ability to identify strangers, and would decease the overall sense of security felt by the inhabitants (http://www.pitt.edu/~murp95/murpwork/plan_s97/students/mmpln97/ass4.html). Despite the impact it had, the ideas set forth by Jacob's did not reach any specific implications for crime prevention until Newman came out with his own book, Defensible Space (1972). (Murray, 1995) This model of crime control, based on crime prevention through environmental design, also developed out of the public health model, as employed by those in the medical fields. Rather than waiting for some type of disease to strike, it focuses on prevention and early diagnosis. As it, the public health model, relates to crime control, it seeks to uncover why some crimes occur in very specific parts of the city, and not in other parts, as well as to understand what are the real characteristics of these areas that are resulting in such high crime rates. It is also based on the operant learning theory of Skinner that was addressed earlier. In short, human beings respond to the environment in such a way as to maximize pleasure gained from it, and to minimize pain. To prevent and alter individuals from behaving in such a fashion, it is necessary to either remove the reinforcement for criminal behavior, or punish the response after the reinforcement has been gained. The model that Newman chose to focus on was the removal of the reinforcement. Without such reinforcement, an individual will not respond to an environmental stimulus.

Crime prevention as a method of explanation and understanding is based on the behavioral sciences, including: urban design, human ecology, neurology, psychological learning theory, sociology, environmental psychology, geography, etc... These are all also key factors in the development of crime prevention programs, such as those done by Newman, and through his ideas. (Jeffery, 1990) Ecology is also very important in the crime prevention models. Early research conducted in France found that some police precincts had extremely high rates of crime, while others had low rates. Property offenses were found to be occurring most often in industrial areas, while violent crimes occurred more predominantly in rural areas. This study was the first to use maps to relate crime to locality and social factors. (Einstadter and Henry, 1995) Similar studies were conducted in England. The assumptions deduced from these early studies can still be found in the ecological analysis being conducted today. These assumptions include: the level of analysis varies from inner-city data to national data, and the unit of analysis is most often the individual criminal, where they live, and not the individual crime site. The Chicago School of Social Ecology continued with these ideas, and some of the major figures preceding Newman's mark on the theoretical world of crime prevention through environmental design include: Burgess' "zone of transition", Brantingham & Brantingham's concentric circle theories, and Shaw & McKay. Social Area Analysis of the 1960s and 1970s focused itself more on aggregate data, which could lead to problems of generalizability. The ecological fallacy inherent in this type of discussion was immediately felt, and it soon came to be considered that there were no causal variables between ecology and delinquency (Jeffery, 1990). Ecology as an approach is extremely important, as it is basic to the study of adaptation of organisms to their environments, using both genetic and learned response patterns.

Crime Prevention Through Environmental Design, outlined by Jeffery, is based upon operant conditioning, psychobiology, and the physical environment. Two critical elements of his discussion relating to crime prevention are: the place where the crime occurs, and the person who committed the crime (Jeffery, 1990). It is interested in why certain areas experience high rates of crimes, or specific types of crime, and it greatly influenced the work of Newman.

POLITICS, COMMISSIONS, ADMINISTRATIONS, AND PROJECTS

Politically, the time prior to Newman's emergence on the scene, and during his time, there were many commissions, administrations, and projects centered on this new theory of crime. The initial attraction of the defensible space theory lay in its potential for policy. Prior to this it was deeply ingrained in the minds of the public and the policy makers that crime was basic in social and economic conditions, so that nothing could be done about it. Newman's physical design changed altered this way of thinking. (Murray, 1990) The federal government put millions of dollars into Newman's ideas, through the Law Enforcement Assistance administration, calling it the Crime Prevention Through Environmental Design project. It established three projects; one for schools, one for commercial areas, and one for residential areas.

Social change was extremely prevalent in a no more dramatic fashion than in Chicago in the late Nineteenth and early Twentieth Centuries. Chicago became a melting pot for a variety of racial and ethnic groups. These groups immigrated and began to work in the factories that were erected in the middle of the city. The lives of these individuals were hard, as well as were their living conditions. The scholars of the Chicago School quickly saw the need to study the traits of the neighborhoods and their shifts and changes, rather than the need to study the individual offender. This line of inquiry was extended into the work of such noted theorists as Shaw & McKay, and Ernest Burgess. (Cullen and Agnew, 1999) The issue of housing also had a variety of considerations given extra notice in the early 1970's. Issues such as location, privacy, investment and symbolic characteristics came to the forefront. (Foley, 1980) In 1973, the Annual Housing survey included selected measures of neighborhood quality. Legislation and programs dealing with the issue of housing began to include a broad framework dealing with community development. The 1970s provided new large scale social experimentation in terms of public housing, such as the Experimental Housing Allowance Program, sponsored by the U.S. Department of Housing and Urban Development (Foley, 1980).

The historical, political, and social environment in which Newman was developing his Defensible Space theory provided a fertile soil for his ideas to grow. The time seemed ready for new theories and ideas to be brought to the forefront as the theories of the day were not providing new insight. With various theorists to pave the way for him, Newman was able to push his ideas out into the limelight and create crime prevention implications that made people rethink the issue of public housing and its elements.

SUMMARY OF ORIGINAL THEORY

Oscar Newman developed his theory after publishing his seminal work, Defensible Space, in 1972. His theory came at a time when crime had become a major issue (Murray, 1995). The 1960's was a period in which crime was deeply embedded in basic social and economic conditions, that it was believed that little could be done until those conditions were changed. Newman believed this to be too pessimistic, and believed that a changed physical design could release the latent attitudes tenants felt, and allow them to assume behavior necessary to protect their rights and property (Murray, 1995). In this work he reported on crime rates in low-cost housing projects in New York City. In his study he found that higher crime rates were associated with high-rise apartment buildings, than those three or five story buildings in comparable social settings. In high rise buildings, 55 percent of the crimes were committed in interior public spaces, as opposed to only 17 percent in the low-rise buildings (Newman, 1972). Interior public spaces included such areas a hallways, elevators, stairwells, and lobbies.

Newman's theory consisted of several concepts used to explain defensible space, including: image, territoriality, surveillance, and safe zones.

1Territoriality is the feeling of possession and belonging by the inhabitants for their building. This concept came from Robert Ardrey's work on territoriality and animals, and how it applied to human behavior as well. It was argued that people perceive areas and spaces as their own, which can and should be defended. It also includes the idea of community, those who feel a sense of community with other residents will be more likely to protect and defend against the presence of outsiders and intruders. With a proper design, it was believed that real and symbolic barriers could be constructed to help establish this sense of territoriality. A family that has a sense of territoriality about the entryway to its apartment will more likely defend it against intruders than a family who does not have this sense of territoriality. A duplex apartment where neighbors are cognizant of who lives next door, will likely to be more aware of outsiders than a neighbor in a high rise or even a quadruple would (Murray, 1995).

Surveillance relates to the ability of the inhabitants to observe their own territorial areas. The observability of crime can be improved by creating areas of space that increase the number of observers, as well as increasing the probability that an offender would be seen in the act.

Images are the stigma or lack of stigma related to an edifice. Offenders will be deterred or encouraged by the visual cues given to them from the space and its inhabitants. This aspect of his theory closely relates to Wilson's Broken Windows Theory. If there is an outward appearance of care and respect for the neighborhood and living area, this will be shown to offenders. The Broken windows Theory indicates that if a window is broken in the building, and does not get replaced or fixed quickly, this lets outsiders feel as if no one cares for the building, and soon, many more windows will be broken, and more acts of crime will take place. A place that looks as if there is a sense of ownership and respect surrounding it will be less likely to be vandalized.

"Safe zones refers to the general location of the building in respect to streets, parks, and other physical features of the neighboring environment" (Jeffery, 1990). Newman recommended that barriers needed to be created between the private, public, and semipublic space. To do so would increase private space and in turn make it defensible space (Newman, 1972).

Informal social control is at the heart of this theory. By creating a acknowledging between the man made environment and crime, the community is exerting pressure to prevent any violations of its norms. The rationale is that defensible space will increase the effectiveness of these informal social controls, and this will in turn reduce crime (Murray, 1995).

Many studies were conducted utilizing this framework, and it was also discovered that fear of crime, building size, accessibility, low income, teenage/adult ratios, and instability of residential occupancy were associated with crime rates (Jeffery, 1990). These principles have also been studied in England and have shown to be an ineffective way to reduce crime, or deter it. Other studies in America showed that Newman was making a basic assumption of believing that the residents would perform the role of surveillance, which in actuality was a police function. These findings made some small changes in the way Newman looked at the problem using his model. He began to look more at social control and social defense by the residents, who were themselves part of a social network. This also proved ineffective. It basically was not working because of a lack of surveillance done on the part of the resident. It was believed that only those with the actual function of surveillance as part of their jobs made any attempt at reporting crimes to the police. It was also shown that this model would work least effectively in areas in which the crime rate is at its highest, but will work in areas where the residents feel allied amongst themselves. Other changes were made in later years, although they were those of degree, and not of kind. Additions to the theory to include other aspects of neighborhood change were included. Such things as the creation of cul de sacs, narrowing of intersections at the entrance to residential neighborhoods, increasing pedestrian traffic, various street lighting projects and demarcating boundaries of the neighborhood, all were extensions of Newman's theory (Murray, 1995).

While the basic tenants of Newman's model stayed in line with his work in Defensible Space, slight modifications were made in the changing times. With the later emergence of theories relating to crime prevention through environmental design, Newman's theory was again looked at as a reference point, with additions and theories being built off of its original ideas.

CRITICISMS AND ALTERATIONS

Newman's critics are large in number, relative to the small amount of work he produced for this theory of crime control. During the time Newman was working on his ideas, preventative methods of crime control relating to the environment, were new to the general public, as well as to those in the disciplines of criminological thought. This section's discussion will be done on the major criticisms of Newman's work, and will then be followed by a discussion of how these criticisms changed the way Newman approached his model and developed his theory in later years. Newman never changed his theory in a large way, he simply revised it as seen necessary by the changing times.

Some of the major critics of Newman's work came from individuals who conducted similar studies in other countries whose conclusions differed greatly from Newman's in respect to the amount of crime in high rise apartment buildings as opposed to low-high rose buildings. Several critics also declared that Newman's methods were methodologically unsound. Mawby found Newman's study to be inaccurate, according to his own study of London high-rise projects, which did not have a higher crime rate than those that were low high-rise projects (Mawby, 1977). Mayhew also found that the principles exemplified by Newman's defensible space theory did not hold up in England (Mayhew, 1979). Tyler, Gottfredson, and Brower stated that the defensible space position is based on many erroneous and untested assumptions. They believed that the modifications suggested in defensible space were not successful in deterring crime (Tyler, et al, 1980). Taylor and his associates also made a relevant point and one of the major criticisms of this model, in stating that the surveillance aspect of the theory rested a lot of assumptions in its belief that residents will exercise a policing function by making use of surveillance ( Taylor, et al, 1986). Later in his work, Newman addressed this issue and how it related to his theory. He began to concentrate his efforts more on the aspect of social control and social defense by the residents themselves, as part of a social network. Mayhew (1979) also confirmed this, stating only those charged with the function, such as the police, etc... will actually employ it and will report crimes to the police.

Greenberg and Rohe conducted an empirical test in 1984 analyzing the effectiveness of Newman's "social control model" versus the model put forth by Jeffrey and Brantingham, the "target and opportunity model." Greenberg and Rohe found a lot less support for Newman's model, and a great deal for the target and opportunity model. In their study, "they used the distribution of targets in relation to major streets, vacant lots, multiple-family units, commercial use, and parking lots where the crime rates were high. In areas with minor streets, single-family residences, few parking lots, and few vacant lots, the crime rates were low" (Jeffery, 1990). After this 1984 article, Greenberg reversed her position in 1986, to support a social control model and fear reduction model of crime prevention. From these studies, she found that the character of the neighborhood had to be filtered through a perception disorder, which produced fear. She then concluded that fear reduction was less than optimal (Jeffery, 1990).

Other problems that have been associated with, and critiqued by this model include issues of displacement and extinction. By preventing crime from occurring in one locale, it does little to deter crime motivation. Those individuals desiring the benefits of crime may choose alternative routes and targets. Crime is then displaced and not prevented. Extinction also comes into play in the aspect that these prevention strategies of defensible space, can possibly produce short-term benefits and changes, but will slowly be overcome once criminals make changes and adjust to the new conditions (Siegel, 1995).

Other critics have defended Newman's work, but have also suggested ways of improving upon its effectiveness, which have led to some changes in the way defensible space theory is utilized. Murray (1983) spoke of how the model may have the least amount of effectiveness in places with the worst crime rate problems, but how it will work in areas in which the community and neighborhood areas are already allied (1983). Murray also stated that Newman's theory rested on one belief that residents would change their behavior, defending their space against criminals. This would be possible through the right physical design, however Murray believes this has not been demonstrated. Murray believed that the wrong physical environment may deter some people, but providing a better physical environment has not been proven to produce new anti crime behaviors. He also stated that as a theory, defensible space holds some utility, in combination with some other measures and in the context of neighborhood characteristics. However, these effects are modest and inconsistent. Murray also discussed the evaluations of Newman's projects and their relative effectiveness. Most of the studies showed signs of more "neighboring" and a greater sense of territoriality, but no consistent reduction in crime. This is one of the major criticisms noted throughout the literature dealing with defensible space. A vast majority of the critics state that a minimal lack of reduction in crime is the major downfall with this theory. A reduction in crime, or even if it could be seen as a valid preventative measure would increase the acceptability by criminologists and sociologists.

Another change that Newman made in his theory came with the instillation of street lighting projects. Instead of focusing purely on environmental changes in high rise buildings, street lighting issues came to the forefront of his discussion. In analyzing these projects, it was found that no statistically significant reduction in crime could be seen. A reduction in the fear of crime was also a new aspect added in later years. It was hypothesized by advocates of the theory that the built environment could reduce the fear of crime independently of effects on crime itself. The rationale behind this is that fear can affect everyone, and fear is often exaggerated. When people have an unreasonably high level of fear, it is good to reduce it, even if the actual crime rate stays the same (Murray, 1983).

By the mid 1980's, the defensible space theory was modified slightly. Territoriality was still seen as an important concept, however, not much was known about whether it could be applied to practical problems of crime prevention. Issues of natural surveillance were still discussed, however, the evidence for it was quiet ambiguous. Image and milieu had an effect on individual's perceptions on their living spaces, but not on crime. It was determined by Murray that "physical changes may facilitate social cohesion and thereby increase informal social control, but only when supplemented by community organizing efforts, better policing, and improved police-community relations" (Murray, 1983). Since this time, the continued interest in defensible space has shifted from public housing projects to innovations that are supposed to make single family houses more defensible.

The changes in the physical environment proposed by Newman led to many critics and proponents of his work and crime prevention through environmental design. Many of the critics of his work have focused on the fact that the theory has not proven to reduce crime in any substantial way, and it rests too much on the compliance and efforts of the individuals in these living spaces.

CURRENT USAGE AND POPULARITY

Newman's theory of Defensible Space has not lost all of its popularity over the last thirty years. However, recent researchers have not used his model since the 1980's in large numbers. research projects. A review of recent abstracts supplied by members of the American Society of Criminologists and the American Criminal Justice Society showed no one using Newman's name in their abstract since the early 1980's, and the newest abstracts and articles to use his model of defensible space were in the years of 1993 and 1995. A majority of the information published concerning his theory was in the 1970's and first half of the 1980's. No citations were found deploying his methods after the middle of the 1990's. It is still in public use, as a few web sites were found detailing Newman' work and projects which were developed from it. At the turn of the century then, it can then be concluded that Newman's theory is having no substantial impact on the world of criminological research, but it is having an impact in areas of public use.

Newman's theory underwent enormous popularity until the mid-1980's. After this, changes were made in the application of the strategy to different environments, while using the same basic tenants that have been described above. The chief feature of this design strategy was street closure. Some streets were made into cul-de-sacs, while in others, barriers were placed diagonally across a four-way intersection, creating residential loops (Murray, 1995). Results from these operations were mixed, and marked reductions in crime did not occur. Proponents of these design changes state that an immediate reduction in crime is not necessary or plausible in order to call a project a success. A change in the neighborhood characteristics may eventually lead to a more stable neighborhood and lower crime, and this may in itself be considered a major step forward (Murray, 1995). The bulk of research since these design projects has come in the hopes of changing the "natural variation" in design settings (Murray, 1995). The concern here is to first understand whether the differences in design settings are associated with differences in crime, and if so, why. James Q. Wilson's, classic article entitled, "Broken Windows" described how crime and the physical condition of a neighborhood can be directly related. The image is of a broken window which is left unrepaired. This invariably leads to more broken windows. The issue is how to get the neighborhood to care about and fix the broken window, and how to get criminals to see that the neighborhood is not an easy and open target. Subsequently, inhabitants of the neighborhood will begin to grow more fearful of violent crime, and will begin to be fearful of other residents. They will begin to use the streets less often, and this is where criminals see that there are no informal social controls by the neighborhood, and more crime will begin to occur.

Newman's model has had an indirect effect on other theories and crime prevention projects. The basic tenants of his ideas can be seen in a variety of work by other theorists, although he is not necessarily cited in their work. Situational Crime Prevention, is another theory that bases part of its research in the model employed by Newman. However, it focuses more on reducing the opportunity for crime by increasing the efforts and risks an offender must make, and also by reducing the rewards gained by the criminal activity (Murray, 1995). A conservative conclusion of its effects are that it has a proven track record for reducing many specific types of crimes at specific locations, and also has more diffuse positive effects as well, of less magnitude (Murray, 1995). Shelley also developed a model of social change in 1981 based on the concepts of urbanization and modernization. She noted that historically, as urban areas developed, as did high rates of crime. Rural areas are noted for higher rates of violent crimes, but through urbanization, property crimes became much more prevalent than their violent counterpart (Jeffery, 1990). Crime Prevention Through Environmental Design is closely related to Newman's Crime Prevention Through Urban Design. In 1985, Jeffrey, established a project in Tallahassee dealing with the issue of environmental design and how it related to convenience store crimes. A similar project was conducted in Gainesville. The Home Office in London has been very active in the area of crime prevention and environmental design. Also, a great deal of attention has been placed in the use of target hardening devices to prevent crime. Neighborhood watch programs can also be seen as a spin off of Newman's basic ideas (Jeffery, 1990). An article by Wolfer (1999) discusses the current use of problem solving policing as it related to crime prevention through hot spot analysis, crime prone areas, and particularly through the use of a new strategy called SARA.

Many projects have been created as a result of some of Newman's basic ideas of defensible space. HUD has begun using defensible space ideas in all of its projects, including which projects to tear down (http://www.defensiblespace.com/author.theauthor.htm). HUD has begun using this approach in response to the growing concern about crime and its effect on the quality of life experienced by those residents of public housing. Three main strategies employed by CPTED programs, and defensible space have been utilized, including: natural surveillance, natural access control, and territorial enforcement (http://www.hud.gov/progdesc/cpted.html). HUD has studies three such projects that have been created and have described them as successful. One was a modification of row-houses in the South Bronx in New York City. Such strategies included the use of fencing and curbs, as well as lighting, paths, and play equipment to improve the appearance of the area. A 54 percent drop in crime was noted after the first year of implementation. In Dayton, Ohio, mini-neighborhoods were created from an urban grid of residential streets to show the community more than closing the streets needed to be done. It emphasized a high level of citizen participation. In Yonkers, New York, public housing families living in high rise buildings were placed into townhouses in middle class neighborhoods, integrating designs with the surrounding neighborhoods, along with training residents in home maintenance (http://www.huduser.org/periodicals/rrr/newman.html). An article discussing current uses of crime prevention through environmental design was also found in the US Department of Justice archives on-line (http://www.ncjrs.org/txtfiles/physenv.txt), although it did not discuss any projects relating to the ideas of defensible space other than those already mentioned. The Institute for Community Design Analysis is designing programs dealing with crime prevention and the stabilizing of the community throughout many cities in the United States. The changing of the physical environment based on Newman's ideas is prevalent in their plans, and in providing these inexpensive physical changes, they are hoping to reduce crime, improve the property values, and create stable economic and racial mixes (http://www.defensiblespace.com/author/projects.htm), (http://www.defensiblespace.com/insitute/theinstitute.htm).

Newman's defensible space model has enjoyed popularity over the years. While it has been waning recently, it is apparent that some of his basic tenants are still alive in theories and research today. While he may not be the most cited reference, he is still a critical part of environmental criminology, and crime prevention through environmental design.

Works Cited

Crime Prevention through Environmental Design. Retrieved November 26, 2000 from the World wide Web: http://www. hud.gov/progdesc/cpted.html

Cullen, Francis T. and Robert Agnew. (1999). Criminological theory: past to present, essential readings. Los Angeles: Roxbury Publishing Company.

Einstadter, Werner and Stuart Henry. (1995). Criminological theory. Fort Worth: Harcourt Brace College Publishers.

Foley, Donald L. (1980). The sociology of housing. Annual Review of Sociology, 6: 457-478.

Jacobs, J. (1961). The death and life of the American city. New York: Vintage.

Jeffery, C. Ray. (1990). Criminology: An interdisciplinary approach. New Jersey: Prentice. Hall.

Mawby, R.I. (1977). Defensible space: A theoretical and empirical appraisal. Urban Studies, 14:169-179.

Mayhew, P. (1979). Defensible space: The current status of a crime prevention theory. Howard Journal, 17: 150-159.

Murray, C. (1983). The physical environment and community control of crime. In J.W. Wilson (Ed.) Crime and Public Policy, (pp. 349-361). San Francisco: ICS Press.

Newman, O. (1972). Defensible Space. New York: Macmillan.

Retrieved November 26, 2000 from the world Wide Web: http//www.defensiblespace.com/author/projects.htm

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Safer environments through urban design: the effectiveness of the defensible space approach. Retrieved November 26, 2000 from the World Wide Web: http://www.pitt.edu/~murp95/murpwork/plan_s97/students/mmpln97/ass4.html

Siegel, Larry J. (1995). Criminology. St Paul, Minnesota: West Publishing Company.

Taylor, R.B., and S. Gottfredson (1986). Environmental design, crime prevention: An examination of community dynamics. In A.J. Reiss and M. Tonry (Ed.'s) Communities and Crime, Vol. 8, Crime and Justice Series, Chicago: University of Chicago Press.

Tyler, R.B. et al (1980). The defensibility of defensible space: A critical review and a synthetic framework for future research. In T. Hirschi and M. Gottfredson (Ed.'s) Understanding Crime, Beverly Hills, Calif.: Sage.

Wolfer (1999). Problem-solving policing. FBI Law Enforcement Bulletin, 68: 9-15.