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1 CRIME’S ECOSYSTEM Marcus Felson School of Criminal Justice Rutgers University DIMACS talk New Brunswick, May 21, 2007.

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Presentation on theme: "1 CRIME’S ECOSYSTEM Marcus Felson School of Criminal Justice Rutgers University DIMACS talk New Brunswick, May 21, 2007."— Presentation transcript:

1 1 CRIME’S ECOSYSTEM Marcus Felson School of Criminal Justice Rutgers University DIMACS talk New Brunswick, May 21, 2007

2 2 Plan for today I talk fast A. Orientation (five slides) B. Fundamentals of Crime Ecology (five sides) C. Crime Foraging (ten slides) D. General Theory of Crime Ecology (seven slides) E. Baby Mathematics (we’ll see)

3 3 Part A – Orientation On five slides

4 4 A1: Not Obvious We can’t build criminology on a few bad menWe can’t build criminology on a few bad men Nor a few bad areas of town –Nor a few bad areas of town – –Traditional “ecology of crime” (1930s) large “social areas” within cities –But recent data and theory show very local variations –A high crime area contains low and moderate crime areas! My goal: To be obvious afterwardsMy goal: To be obvious afterwards

5 5 A2: Not Simple Illegal activities feed off legal activitiesIllegal activities feed off legal activities Local crime is part of a system of activitiesLocal crime is part of a system of activities That means we need ecologyThat means we need ecology Not natural for criminologists or police to study crime as a systemNot natural for criminologists or police to study crime as a system Not natural for ecologists, biologists, to include crimeNot natural for ecologists, biologists, to include crime

6 6 A3: Not Metaphorical Life science, as you probably see it Life science, as I see it Criminology a. I’m using ecological concepts broadly but literally b. I imagine the“Life sciences” to be larger than what you learned in school.

7 7 A4: Not Automatic We can’t do exactly what you do todayWe can’t do exactly what you do today Look back a few hundred yearsLook back a few hundred years My favorite biologist: LinnaeusMy favorite biologist: Linnaeus We have to be true to our topicWe have to be true to our topic

8 8 A5: Not Genetic Useful topics: foraging, defense, symbioses, habitats, crime settingsUseful topics: foraging, defense, symbioses, habitats, crime settings Less useful topics: differential reproduction or mortalityLess useful topics: differential reproduction or mortality Species is not the unit – crime applies to all homo sapiensSpecies is not the unit – crime applies to all homo sapiens Our task: To describe and catalogue illegal activities,Our task: To describe and catalogue illegal activities, not species. not species.

9 9 Part B – Fundamentals of Crime Ecology On five slides

10 10 B1: Crime is ordinary a)Thousands of thefts for every murder b)Thousands of quarrels for every escalation c)Booze abuse > extreme-drug abuse d)Most crime in gang areas is non-gang e)“Organized crime” seldom very organized f)Stealing password from your desk g)Even serial killers follow routines, geo-models To understand most crime, stop watching television

11 11 B2: Crime is highly physical Best predictor of burglary rate : weight of smallest TV in the Sears CatalogueBest predictor of burglary rate : weight of smallest TV in the Sears Catalogue Convergence & DivergencesConvergence & Divergences Physical, but not mechanicalPhysical, but not mechanical Offenders make decisions; motives can varyOffenders make decisions; motives can vary Life sciences or physics ?Life sciences or physics ?

12 12 B3: The Crime Triangle

13 13 B4: Each crime has a sequence Murder isn’t a crime: It’s an outcome.

14 14 B5: Crime is symbiotic in three ways Crime is symbiotic with Examples: Other criminal activities Burglars help each other find victims. A drug addict feeds off shoplifting. Marginal activities A legal prostitute sells illegal drugs. An hourly hotel houses illegal prostitutes. Legal activities A lawyer nibbles from a trust account. A restaurant welcomes local drug dealers.

15 15 PART C Crime Foraging Nine slides sum up three dense chapters in my book, CRIME AND NATURE

16 16 C1: Not all offenders forage Two guys fight in a barTwo guys fight in a bar Family violence seldom requires foragingFamily violence seldom requires foraging Insiders often can steal without foragingInsiders often can steal without foraging But foraging still very importantBut foraging still very important

17 17 C2: Standard foraging principles fit offending (with nuances) Offenders minimize the effortOffenders minimize the effort Offenders minimize the riskOffenders minimize the risk Offenders maximize the reward**Offenders maximize the reward** **But not long-term rewards or punishments! Plenty of empirical verification

18 18 C3: Offenders are relative generalists Offender Versatility Use this to reduce crime Diet breadthFairly versatileReduce targets, crime benefits Hunting methodFairly versatileRemove easy crime options RangeNot very versatile** Narrow the range of targets **

19 19 C4: Offender awareness space

20 20 C5: Repeats A good deal of repeat victimization – same residence or businessA good deal of repeat victimization – same residence or business Poisson distribution over time, wider intervalPoisson distribution over time, wider interval Near repeats, next door or two doors down, Poisson distribution over spaceNear repeats, next door or two doors down, Poisson distribution over space

21 21 C6: Offenders forage for items they can carry or overcome Here I am stretching “bigger than his head”Here I am stretching “bigger than his head” Applies to personal and property crimesApplies to personal and property crimes An offender overcomes personal reach withAn offender overcomes personal reach with –Accomplices –Vehicles –Tools

22 22 C7: Offenders minimize handling time Handling stolen goodsHandling stolen goods When traveling farther, expect greater gainsWhen traveling farther, expect greater gains These rules assist crime prevention.These rules assist crime prevention. “Opportunity Makes the Thief” correct“Opportunity Makes the Thief” correct

23 23 C8: Foraging affected by risks Other offenders ***Other offenders *** Police, security (who also forage)Police, security (who also forage) Victims, or bystandersVictims, or bystanders Offenders are risk-takers, but go only so farOffenders are risk-takers, but go only so far Drug abuse cycles affect risk-takingDrug abuse cycles affect risk-taking

24 24 C9: Settings rich in crime targets invite New offenders Occasional offenders to activate Active offenders to become more efficient Returning offenders to stop being so good A lot of people commit a little crime. This adds up.

25 25 C10: Sex and foraging People seeking sex or social life are highly vulnerable to crime victimizationPeople seeking sex or social life are highly vulnerable to crime victimization The sexual urge helps lure victims, trick them, distract them, embarrass them, etc.The sexual urge helps lure victims, trick them, distract them, embarrass them, etc. Any sexual rulebreaking is risky: the offender knows the victim won’t reportAny sexual rulebreaking is risky: the offender knows the victim won’t report

26 26 Part D Building General Crime Ecology A 400 page book in Seven Teaser Slides

27 27 D1: Eight primary defenses against crime Go over these fast 1.AvoidanceWalk in safer areas 2.CamouflageDress like a student 3.Batesian mimicryLook tough 4.Müllerian mimicry**Wear gang colors 5.WarningsPut up warning sign 6.Physical defensesLocks, bolts, armor 7.Group defensesWalk in a pack 8.Vigorous recoverySell more, swamp thefts ** My favorite – no time to go over now

28 28 D2: Seven secondary defenses apply, too but I’ll move on unless you stop me Move away from adversaryMove away from adversary Communicate ability to escapeCommunicate ability to escape Distractions, feigns, and startlesDistractions, feigns, and startles Symbiotic protectionSymbiotic protection Chemical and weapon defensesChemical and weapon defenses Sudden weaponrySudden weaponry Emergency social defensesEmergency social defenses

29 29 D3: Three types of Crime Mutualism Again – This fits larger ecology Exchange resources: Drug buyer & drug seller Stop mutual enemies: Gangs & drug dealers vs. police Spread and reproduce: Entertainment newspaper that advertises prostitutes

30 30 D4: Aegism and crime (my favorite) Phoresis barnacle, whale Helping offender move about Mass transit, lifts from friends Epizoism coral reef Find quick refugeCavernous public housing Inquilinism good bacteria Find shelter in site still used Soliciting inside train stations Endoecism hermit crab Find shelter in abandoned site Drug abusers in abandoned building

31 31 D5: Three Types of Crime Habitat

32 32 D6: Fragmentation Ecologists warn against forest fragmentationEcologists warn against forest fragmentation But we WANT crime’s habitat to be fragmented!But we WANT crime’s habitat to be fragmented! We want to reduce crime’s biodiversityWe want to reduce crime’s biodiversity When a local “colony” dies out, we don’t want it to recoverWhen a local “colony” dies out, we don’t want it to recover

33 33 D7: Urban Policy Strategy Keep narrow crime habitat from thickeningKeep narrow crime habitat from thickening Keep two narrow crime habitats from growing togetherKeep two narrow crime habitats from growing together Try to fragment thick crime habitats that already existTry to fragment thick crime habitats that already exist

34 34 Part E Baby Mathematics Simple ideas, easily complicated

35 35 Problem 1: How did this happen? Note five open-air drug markets of varying sizes They grew outwards, producing a thick crime habitat

36 36 Prob. 1, cont. Fractal-like spread of drug markets George Rengert’s ideas, my version

37 37 Prob.2: Abandoning & Supervising Space One abandonment encourages another, and all encourage crime

38 38 Prob. 3: One crime leads to another – Direct burglary multiplier model The sequence: 1.a burglary occurs, property is taken. 2.the burglar sells these stolen goods, 3.to someone who knowingly buys them 4.who re-sells these stolen goods continued>

39 39 Prob. 3, Cont: The Accounting Initial burglaries1,000 Subtract cash burglaries -580 Non-cash burglaries 420 First sale of stolen goods 406 F irst purchase of stolen goods 406 Resale of stolen goods 365 Total crimes generated 2,177 CRIME MULTIPLIER =2.177

40 40 Prob. 4: Easy Needle Policy Vancouver’s easy needle policy probably improves safety for current drug abusers at any given injection.Vancouver’s easy needle policy probably improves safety for current drug abusers at any given injection. But it also seems to draw other drug abusers to Vancouver!But it also seems to draw other drug abusers to Vancouver! New Jersey is adopting parts of such a strategyNew Jersey is adopting parts of such a strategy Unfortunately, drug abusers are a hard population to trace, but here’s my thinking.Unfortunately, drug abusers are a hard population to trace, but here’s my thinking.

41 41 Prob. 4, cont: Disaggregate Disaggregate The Population Of Drug Abusers Disaggregate The Population Of Drug Abusers T t = Total drug abuse population in year t N t = New local drug abuse population in year t M t = Deaths of local drug abuse population in year t D t = Desisting local drug abuse population in year t I t = In-migration of drug abusers to local area in year t O t = Out-migration of drug abusers from local area in year t

42 42 Prob 4, Cont: Basic Equation ( a) T t = T t-1 + N t - M t - D t + I t - O t Rearranging, (b) T t = (T t-1 + N t + I t) - (M t + D t + O t )

43 43 Prob 4: Explained In other words, this year’s drug abuse population is augmented by three components and depleted by three other components. Augmenting the drug-abuse population: Last year’s surviving local drug abuse population, Last year’s surviving local drug abuse population, New local abusers, and In-migration of abusers to the local area from elsewhere. Depleting the drug-abuse population: Deaths of local drug abusers, Desistence of local drug abusers, and Out-migration of local drug abusers.

44 44 Thanks to those who lasted Marcus Felson


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