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There are
many possibilities to use precedents in the field of crime prevention
and crime analysis. SAFE PLACES (VEILIGWONEN.NL) thanks Rob van
der Bijl for the following summary of his topic 'Evaluating Crime Prevention
in Public Housing'.
Within
crime prevention the prevention of burglary represents a clearly demarcated
and full domain of police know-how. Both in theory and in practice the
activities of burglars have been investigated. Scientists and police
officers are well informed about their modus operandi. Besides,
a lot of ex-perience has been gained in Dutch cities, for example, with
the implementation of preventive measures in the field of architecture,
town planning, administration, electrical as well as electronic engineering.
Crime prevention
can be supported by (large) collections of precedents. Situational aspects
of burglary - such as location, construction type, etc. - form therefore
representative areas of the domain of knowledge which in themselves
al-ready justify the development of 'knowledge-rich' examples.
It appears
possible to take advantage of the potential of precedents to support
the prevention of crime. The Dutch police force (especially in the district
of The Hague) has explo-red this potential during the last few years
by means of applied research methods. The prevention of burglary served
here as a proving ground.
Topologic
Crime Coding
(C) RVDB The Hague/Amsterdam 1991-2003
Paradigms
A theoretical excursion: decision support systems for crime prevention
can be developed on the basis of two paradigms. The representation of
expertise by means of rules expresses the first paradigm. The analysis
and reasoning of the human expert is formalized by means of rule-based
reasoning, refer, for example, to Rich (1983). The second paradigm represents
case-based reasoning. No separate rules, but 'chunks' of knowledge or,
in other words, a complete case represents the demarcated exper-tise.
(Kolodner, 1993)
In the Eighties applications were mainly developed within the first,
that is to say rule-based paradigm. Those applications are usually characterised
by their limited range. Not a complete domain of knowledge, but small,
conveniently arranged areas within their domain of knowledge have been
computerized. Police applications are no exception to that. For example:
an expert system - of American origin - simulates the process of thought
of detectives as far as a specific subject is concerned, namely the
identification of possible suspects on the basis of fingerprints that
have been left behind with burglary. (Ratledge & Jacoby, 1989) Although
that is a very useful application, it only represents a small piece
of knowledge with regard to crime prevention.
A disadvantage
of working with rules is the context independent nature of rules. In
prevention of burglary, public security, crime analysis, but also in
other domains of expertise knowledge has not been laid down unambiguously.
The concepts out of which that knowledge consists have been inadequately
defined. There are rules or there is a possibility to design rules that
enable argumentation with those domain concepts, but the way in which
this has to be done is strongly context dependent. Knowledge only becomes
unambiguous within a concrete situation. The exact significance of concepts
only comes into being while being used. It is very difficult to find
rules with which one can anticipate new (unforeseen) situations. Within
the various knowledge domains there definitely are rules, but those
rules cannot be applied universally just like that. (Kolodner, 1993)
This disadvantage
of rule-based reasoning van be overcome by means of case-based reasoning.
After all, rules represent small, independent pieces of domain knowledge.
Rules are not implemented before given and conclusion have been tuned
to one key (whether or not with some degree of certainty).
Precedents
form large coherent chunks of domain knowledge. Precedents can already
be used even when data are incomplete, or when it is not yet clear what
conclusions have to be drawn. The use of a precedent or case is flexible
indeed. They do justice to the user. Depending on the context, the user
appeals to a case in order to form an opinion, to draw a conclusion,
etc.
ratio
decidendi
A precedent - in the field of burglary prevention - is by definition
representative and manageable. But even still more than that, a precedent
can also be applied, and it carries weight. It concerns what jurists
in practice call the 'ratio decide-ndi' of precedents. A legal case
is not a precedent as a consequence of its reflecting decisions that
were taken, or a certain state of affairs. That would be too neutral
a ground for consideration. A phenomenon - a project, an event, a plan,
etc. - is only translated into a precedent if it will maintain its significance
for future phenomena and cases. Which at the same time also excludes
that in future cases the old precedent will simply be copied. "In
any professional (or indeed common-sense) application of precedent-based
decision-making, consideration of precedents does not mean blind imitation:
on the contrary, an essential part of it is what lawyers call 'distinguishing',
or recognising relevant differences between cases, tracing correspondences
and picking out distinctions that are significant for the purpose in
hand, while ignoring those that are not." (Tzonis & White,
1994)
Precedent:
Blueprint
Storage
The information of each precedents should be stored in the form of data,
texts, graphics and pictures. These media represents a particular precedent
on at least four levels.
The first of the four levels is the context, or in other words the project
surroundings. The second level documents the project itself, which could
be a housing block, a school building or a plaza. The third level relates
to a distinctive part of the project such as for example dwellings or
classroom adjacent to a corridor. Finally the fourth level houses the
individual elements of the project. This could be a individual dwelling,
a school-entrance with porter's lodge, or one corner of a plaza.
Five ways of image representation range from concrete to abstract. They
are successively:
realistic pictures (or drawings or design sketches)
blueprints (or topographic maps)
schematized plans and sections
spatial syntax of a plan
adjacency diagrams
crime-related knowledge
Precedent:
schematized plan
The schematic
representation is the most important image. It eliminates many details
from blueprints or topographic maps but on the other hand devides, as
additional security and crime-related knowledge, the territory in public,
semi private and strictly private domains. According to what the level
permits, the schematic reproduction is detailed with additional information
about for instance window openings and other safety related data. Everything
according to a strict graphic representation, specifically designed
for the practice of precedent-based decision support. In addition, criminality
statistics and related subjects, are marked by means of a topological
crime coding. Pictograms locate crime events.
Users
Precedents serve varied ways of usage. And although the amount of different
users will be very large, it is possible to make some general distinctions
in the user population. Potential users can be stereotyped and categorized,
for example, into the three following characters:
police officers
managers
architects
Each character
departs from a different background and formulation of the problem and
therefore will have different expectancies in relation to desired functionality.
The objectives of the three characters each differ accordingly. Designs
or realized plans contain many aspects. The police user is only interested
in crime-related topics. The architect on the other hand tries to integrate
all aspects in the design, while the manager is pragmatic. He will try
to realize all (or as many as possible) different aspects.
Precedent-based
reasoning
Evaluating interpretations
defines the reasoning of the manager. Evaluation is also typical of
the police officer. His or her emphasis is - besides on interpretation
- also on projection. The police officer evaluates the design by projecting
its crime-related properties into the future when it will be implemen-ted.
The architects position is entirely different. When creating, evalation
does not have priority. In other words, a designer generates. He is
a problemsolver.
The police officer contrasts an analogue situation to the situation
at hand. The manager does the same. The police officer also benefits
from a highly disparate design which enables him to get a better projection
of the future implementation of the design he has to evaluate.
The designer doesn't reason immediately towards an endgoal (such as
optimal security) but tries many disparate avenues of solution. And
therefore would want to view as many similar and different situations
in light of the particular situation he is working on.
In principle,
the possibilities for precedents to support activities in the field
of crime prevention and crime analysis are unlimited. After all, a large
collection of precedents could document the entire built environment,
including the environmental pattern of crime and the logistics of the
localized criminal offences.
Precedent:
Adjacency Graph
ACKNOWLEDGEMENTS
Rob van der Bijl; PRECEDENT BASED CRIME PREVENTION
Contribution
to the 47th Annual Conference of the American Society of Criminology
Boston (MA), November 14-18, 1995
Illustrations & Editing for SAFE PLACES:
Rob van der Bijl (RVDB), Amsterdam Netherlands, January 2003
REFERENCES:
J.Kolodner;
Case-based reasoning. San Mateo 1993.
E.C.Ratledge
& J.E.Jacoby; Handbook on artificial intelligence and expert systems
in law enforcement. New York, etc.1989.
E.Rich;
Artificial intelligence. New York 1983.
A.Tzonis
& I.White (eds.); Automation based creative design. Research and
perspectives. Amsterdam 1994; Introduction, pp.1-40.
R.A.J.
Van der Bijl; PREDORE 'outline' version 2.10. Contribution to ALBERTI
Euroconference II, Design Knowledge Systems, Precedents in Creative
Design. Delft University of Technology. December 15 1994.
LINK
RVDB: Urban
Planning & Crime Prevention Specialists
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