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Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George F. Rengert Department of Criminal Justice Temple University Philadelphia, PA. 19122 [email protected]
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Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Jan 03, 2016

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Page 1: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Spatial Clustering of Illegal Drug Dealers:

Swarming for Safety or Agglomeration for Profit

Dr. George F. Rengert

Department of Criminal Justice

Temple University

Philadelphia, PA. 19122

[email protected]

Page 2: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Where can illegal drug markets locate? Folk wisdom: any where they want to. Scientific knowledge: any where they want to as

long as: Safe from neighbors and detection by police. Profits can be made.

Safest areas to sell drugs generally thought to be in socially disorganized areas. If not socially disorganized, may experience

resistance from neighbors. Example from North Philadelphia:

Page 3: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 4: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

But most socially disorganized areas may be least profitable areas. Lack local demand—abandoned houses.

Drug dealing can lead to abandoned houses as more people sell than buy houses in this community.

Would you buy one of these houses located in a drug sales area of North Philadelphia?

Page 5: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 6: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 7: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

The following is an example of housing abandonment measured by tax delinquency around a drug sales area.

Page 8: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 9: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 10: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Which is it, profit or social disorganization?

Critical issues concerning profits in retail operations: location, location, location. Good locations allow:

ready access attract large numbers of customers increase the potential sales of retail outlets.

Page 11: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Retail market analysts commonly use demographic variables to predict market share = Demographic Profile. Who is likely to purchase illegal drugs?

Young adults aged 15 to 29. High school drop-outs. Unemployed.

Marketing geographers have developed several strategies for determining optimal locations of retail firms.

Location-allocation model most often used. Includes: the objective function, demand points,

feasible sites, a distance matrix, and an allocation rule.

Page 12: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

We use the objective function of maximizing sales volume by minimizing distance to potential customers identified by the Demographic Profile.

Data from Wilmington, Delaware. Demand points = centroids of census tracts. Distance matrix = distance between centroids of

. census tracts.

Allocation rule = customers assigned to the census tract that minimizes total distance traveled by potential customers for illegal drugs.

Assumption = all users in city purchase drugs at

this census tract

Page 13: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Would have to travel the fewest person-miles if illegal drug market was located in census tract 1600.

This tract was fourth from the highest in reality.

Limitations of the simple form of location-allocation model: Planar model = any location in city is a potential

site. Residents of expensive housing areas not likely.

Masked out areas where medium housing values above average.

Local addicts will travel any distance for drugs. Assigned zero to distance if beyond a mile, 1 if less.

Page 14: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Distance matrix is replaced with zeros and ones. Two clusters of census tracts identified:

2200, 2300, and 1400. 602 and 601. Surprise: not in the center of the city.

Page 15: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

The analysis yielded two clusters of census tracts. The census tracts that ranked first, second and

third formed the first cluster. The census tracts that ranked fifth and sixth the

second. The preceding map portrayed this analysis.

It is not census tract 600 or 1600 that are in the center of the city.

Rather it is a group of census tracts that are in the center of a population of potential drug users.

Rather large areas. We need specific sites for our drug market. Requires more refined analysis possible with GIS.

Page 16: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

What can Geographic Information Systems do for us? Compare traditional analysis with what possible

with GIS:

Traditional analysis assigns features to census space. Census tracts. Block groups. Block faces.

Census boundaries are set and determine the spatial nature of the analysis.

Page 17: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 18: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Refined method: Create GIS buffers about features and allocate

proportion of area of tract that is within buffer. Advantages:

Feature does not have to be in tract to impact it.

Impact is proportional to size of tract.

Disadvantages:

Assumes impact uniformly distributed across entire tract.

Proportion not site specific.

Page 19: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 20: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

GIS method: Create new geographies with buffers around

features. Create ‘interaction effects’ with overlays of

buffers. Advantages:

Does not assume effect is uniform over census tract. Buffers can be sized to reflect spatial reach of a feature.

Disadvantages: New geographies vary markedly in size. Small slivers created that lack geographic meaning. Zero counts overrepresented.

Page 21: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 22: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Drug Market Analysis of Wilmington, Delaware, GIS. Initially start with census data at block group level.

Local Demand: 1. Percent of population age 14 to 29. 2. Unemployed males. 3. Percent of population over age 18 with less than a high school education. 4. Median Income. 5. Number of children under age 5 living in poverty. R2 = .467

Page 23: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Identify features that attract potential drug users.

Routine activities create ‘crime generators.’ Schools, taverns, homeless shelters, etc.

Create buffers around these features to determine their areal reach if any.

Use location quotients to determine if feature associated with spatial aggregation of drug dealers.

Page 24: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

LQ = CR / CN

CR = Number of drug arrests per square mile in

GIS identified area.

CN = Number of drug arrests per square mile in

entire city.

Page 25: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Accessibility Buffers Location Quotients

400-ft Major Roads 1.49 600-ft Major Roads 1.30 800-ft Major Roads 1.20

400-ft I-95 Exits 0.59 800-ft I-95 Exits 1.10 1200-ft I-95 Exits 1.41 1600-ft I-95 Exits 1.76 2000-ft I-95 Exits 1.65

400-ft Transit Locations 1.66 600-ft Transit Locations 1.13 800-ft Transit Locations 0.98

Page 26: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 27: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Major Roads Buffer (mask)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft600 ft800 ft

Page 28: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

#Y#Y

#Y#Y

#Y

#Y#Y

#Y

#Y Train Station

Rodney Square (Bus)

N

EW

S

1 0 1 Miles

I 95 BuffersWilmington, DE

Masked Area2000 ft. Buffer1600 ft. Buffer1200 ft. Buffer800 ft. Buffer400 ft. BufferMajor RoadsI 95

#Y I 95 Exits

Page 29: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 30: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

I 95 Exits Buffer (mask)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft800 ft1200 ft1600 ft2000 ft

Page 31: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

#Y#Y

#Y#Y

#Y

#Y#Y

#Y

#Y Train Station

Rodney Square (Bus)

N

EW

S

1 0 1 Miles

Major Transit Location BuffersWilmington, DE

Masked AreaTransit buff 800.shpTransit buff 600.shpTransit buff 400.shpMajor RoadsI 95

#Y I 95 Exits

Page 32: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Transit Locatons Buffer (mask)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft600 ft800 ft

Page 33: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Local Accessibility

Routine activity nodes. Anchor points of daily activities.

Page 34: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Opportunity Buffers Location Quotient 400-ft Schools 1.19 800-ft Schools 1.04 1000-ft Schools 0.92 1200-ft Schools 0.58 400-ft Taverns 2.30 800-ft Taverns 1.94 1200-ft Taverns 1.71 400-ft Liquor Stores 2.42 800-ft Liquor Stores 1.66 1200-ft Liquor Stores 1.40 400-ft Check Cashing 3.00 800-ft Check Cashing 2.48 1200-ft Check Cashing 2.06 400-ft Pawn Shop 0.10 800-ft Pawn Shop 1.29 1200-ft Pawn Shop 1.54 400-ft Police Station 1.61 800-ft Police Station 1.49 1200-ft Police Station 1.31 400-ft Court 0.48 800-ft Court 0.65 1200-ft Court 0.95 400-ft Fire Station 0.86 800-ft Fire Station 0.87 1200-ft Fire Station 1.03 400-ft Shelter 2.93 800-ft Shelter 3.17 1200-ft Shelter 2.75

Page 35: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

School Buffer (Masked)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft800 ft1000 ft1200 ft

Page 36: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Tavern Buffer (Masked)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft800 ft1200 ft

Page 37: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Liquor Store Buffer (Masked)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft800 ft1200 ft

Page 38: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 39: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Check Cashing Buffer (Masked)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft800 ft1200 ft

Page 40: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Pawn Shops Buffer (Masked)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

LQ

400 ft800 ft1200 ft

Page 41: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Police Buffer (Masked)Location Quotient by Year

-0.50

0.50

1.50

2.50

3.50

4.50

5.50

6.50

7.50

8.50

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997Year

LQ

400 ft800 ft1200 ft

Page 42: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Fire Stations Buffer (Masked)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997Year

LQ

400 ft800 ft1200 ft

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Temple UniversityDepartment of Criminal Justice

Shelters Buffer (Masked)Location Quotient by Year

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997Year

LQ

400 ft800 ft1200 ft

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Temple UniversityDepartment of Criminal Justice

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0 1 2 Miles

N

EW

S

Homeless Shelters

Social Service

Centers

Check Cashing

Stores

Taverns

Liquor Stores

Wilmington, DE

Crime Generators andCriminal Attractors

Page 45: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Homeless Shelters 800 feet

Social Service Centers 800 feet

Check Cashing Stores 400 feet

Taverns 400 feet

Liquor Stores 400 feet

Wilmington, DE

Crime Generators andCriminal Attractors

Page 46: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

The Analysis

Create buffers around point and line features. Assign the buffer areas to census block groups.

Statistically analyze the importance of each variable. Begin with drug sales figures and the plotting of

each feature on a map of Wilmington, Delaware.

Page 47: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Page 48: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Zero Inflated Poisson Model

Two phase analysis. Like analysis of number of children a couple

chooses to have: Choice to have children Choice of how many children to have once decide to

have them.

Page 49: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Factors Associated with the Establishment of a Drug Market Positively Associated:

Percentage of nonwhite residents. As the percentage of nonwhite residents increases, the

chance that the area will never have a drug-market arrest decreases.

The spatial lag term. As the number of arrests in the surrounding area increases,

the chance of the parcel never having a drug-sale arrest diminishes.

Negatively Associated: I-95 exits.

Being located near to an access ramp for I-95 increases the chance that an area will not have drug-market arrests.

Rest not statistically significant

Page 50: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Factors associated with the size of drug markets given that a drug market exists: Positively associated:

I-95 exits. Female headed households with children. Vacant homes. Non-white residents. Check-cashing stores. Liquor stores. Homeless shelters. Spatial lag term.

Negatively associated: Renter occupied units. Social service programs. Taverns.

Rest not statistically significant

Page 51: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Implications of the Study. Significant difference between taverns and Liquor

stores. Place managers of tavern owners?

Negative association between rental housing and drug sales arrests.

Interaction between population density and neighborhood control?

Significance of “spatial lag term.” Is it “Agglomeration economies? “ Is it “social networks?” Is it a result of “spatial diffusion?”

Page 52: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Association between Black population and drug sales arrests. Is it “environmental racism?

Noxious facilities are put in vulnerable neighborhoods

Is it a lack of “social efficacy.” Do not use all the tools available including the police.

Not police “crackdowns.” Rather, prioritize calls for service—create social efficacy.

Page 53: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

Clearly what is needed at this point is contextual analysis to determine interaction effects. We especially see this in the I-95 access.

Not all are bad. But if is bad, is very bad as size of market illustrates.

We also see this in the difference between taverns and liquor stores.

Notice that the difference between location quotients is not great for taverns.

Indicates they might locate in bad areas rather than attracting drug sales.

Liquor stores have greater difference in LQ. In order to obtain contextual variables, can use GIS

to visualize:

Page 54: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Census Block Groups

Wilmington, DE

Page 55: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Homeless Shelters 800 feet

Social Service Centers 800 feet

Check Cashing Stores 400 feet

Taverns 400 feet

Liquor Stores 400 feet

Wilmington, DE

Crime Generators andCriminal Attractors

Page 56: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Single Coverage combined polygons

Wilmington, DE

Crime Generators andCriminal Attractors

Page 57: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Single Coverage combined polygons

Wilmington, DE

Regional Accessibility, Crime Generators andCriminal Attractors

Page 58: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Census Block Groupsand Built Environment

Wilmington, DE

Page 59: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Areas within Buffers of:

Liquor Store or Tavernand I95 Exits and Major Roads

Wilmington, DE

Page 60: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

0 1 2 Miles

N

EW

S

Single Coverage

Census Block Groupsand Built Environment

Wilmington, DE

Page 61: Temple University Department of Criminal Justice Spatial Clustering of Illegal Drug Dealers: Swarming for Safety or Agglomeration for Profit Dr. George.

Temple UniversityDepartment of Criminal Justice

How do you know which interaction effects are significant? Which should you choose?

Answer Tree analysis in SPSS-- interaction trees. Can force first split. Drug Sales Arrests

Low income High income