Good CPTED depends on good decisions and good data
1. Using crime data to identify the PRIMARY CRIME TYPES for a location
Primary crime types for a site are those with the highest incidence. Typically, cthe majority of crime incidents for a location result from a small number of crime types. The crime types, however, may vary between otherwise similar locations. For example, crime at public park A may be primarily theft from vehicle and violence between young men. In contrast, crime at public park B may be primarily drug use and anti-social behaviour.
Justifiable choice of CPTED methods will differ for sites with different primary crime types. Knowing the primary crime types for a site strongly dictates the CPTED methods to be used, and the ability to justify CPTED decisions.
2. Using crime data to identify whether a site is LOW, MODERATE or HIGH CRIME
The CPTED methods and process you use are different for locations with different levels of crime. In some cases, the best decision is not to apply CPTED!
CPTED works best for sites with moderate crime rates. CPTED is often not economically effective for sites with very low levels of crime. For a local government agency, knowing that a site has low or very low crime raises the question 'Why would you commit money to CPTED on a low crime site that could be better spent reducing more crime elsewhere? High crime sites (> 7 crimes per 100 residents per year) typically require specialist CPTED and / or security input to site design.
Whether a site is low, medium or high crime also provides a justifiable basis for budget decisions on the use of CPTED.
3. FEW CRIME TYPES or a GENERAL CRIME RISK?
Locations with a few primary crime types are very different from locations with crime across the full breadth of crime types. Where crime is restricted to a few crime types, decisions on CPTED methods are straightforward and justifiable.
In contrast, sites with a moderate level of crime spread across most or all crime types means there are low levels of crime for each crime type. CPTED is not effective at very low rates of crime and thus hard to justify. In this situation, one potentially valid practice is to identify from the crime data a small number of primary crime types and choose CPTED methods to suit. As the crime situation changes over time, other CPTED interventions may then be justifiably applied as appropriate.
4. Is crime FOCUSED or DIFFUSE? Does the 80:20 rule apply?
Sometimes, crime for a particular land use is high, but detailed crime data shows that crime is focused only on a small number of examples. For example, in Wirral, UK, crime data showed a high level of crime at bus stops. However, more detailed crime data indicated the majority of the crimes occurred at only 35 bus stops out of the total of 1350. These 35 bus stops had VERY high crime rates! A similar phenomenon can often be found in night life areas around clubs, bars and pubs
, where most of the crime may occur at a very small proportion of the establishments.
Where crime data indicates crime is focused on a small proportion of examples of a land use, a more effective CPTED response is to tailor the choice of CPTED methods to each individual problematic location, rather than applying a general CPTED response across all locations.
5. Are there specific VICTIM groups?
In some locations, crime data shows that crime happens primarily to particular victim groups. In this case, effective and justifiable CPTED focuses on choosing CPTED methods to reduce crime in the environments and routine activities of those victim groups. This can offer increased effectiveness in reducing crime rates compared to addressing crime more generally or focusing only on offender groups.
6. Are there specific CRIME ATTRACTORS?
In some locations, crime data can indicate that crime is driven by specific crime attractors, e.g. drug dealing in a nearby park is likely to drive an increase in incidents of theft for money for drugs in nearby areas..
Where the crime data indicates crime attractors may be a strong influence on crime rates or crime types, focusing the choice of CPTED methods on reducing the influence of the crime attractors can be effective and economical.
7. Are ROUTINE ACTIVITIES a dominant factor shaping crime at a location?
In many environments, people’s routines shape crime. For example, many suburbs have few ‘eyes on the street’ during the day. On the offender side, crimes largely depend on the crime opportunities observed during their routine activities each day.
A combination of crime data and observation of the environment can provide evidence of where routine activities of criminals and victims shape crime. In such cases, focusing CPTED resources on reducing the crime effect of routines offers the potential of increased cost-effectiveness.
8. Is there a TIME PATTERN for crime at the location?
Where the time of incident is available in crime data, then sometimes it can be seen that some crime incidents occur primarily at particular times, or on particular days. Focusing the choice of CPTED methods on the primary crime incidents and the times they occur can offer more effective use of CPTED resources.
9. Are there crime ‘HOT SPOTS' at or near the site?
Crime data can increasingly identify specific crime ‘hot spots’ in an area . The primary crime types at these ‘hot spots’ are the obvious basis for choosing CPTED methods.
Experience in the US and UK (and to some extent in Australia) indicates crime ‘hot spots’ are typically not static and they change in intensity and location over time. Where crime ‘hot spots’ have dynamic behaviour, then CPTED methods will need to change over time.
10. What are the CRIME TRENDS for a site?
Crime statistics offer a long-term picture of changes in crime incident rates for different crime types. Clearly, when deciding how best to apply CPTED methods in a location, it is useful to know whether a particular crime type is on the increase or decrease.
Crime trends data also provides useful justification for decisions about CPTED budgets and where budgets should be spent.
For those interested, we provide more detail on all the above in our CPTED training at https://designoutcrime.org/index.php/cpted-training