© 2001 Vito & Blankenship
© 2001 Vito & Blankenship
Learning ObjectivesIn this chapter you will learn
role of statistical analysis in criminal justice
how crime in measured in the U.S.strengths & weaknesses of crime
measuresapplication of statistical analysis in a
criminal justice agency
© 2001 Vito & Blankenship
Introduction
Studying statistics can be important to yourunderstanding of the disciplineprofessional developmentcareerrole as a consumer and a citizen
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Validity of Crime StatsValidity is synonymous with
accuracyAre the ways we measure crime
valid?What are the implications for the
use of crime statistics in planning?
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Ways of Measuring Crime
Two major ways of measuring the amount and types of crimesUniform Crime Report (official data)
changing to National Incident-Based Reporting System
National Crime Victimization Survey
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Uniform Crime Report Crime in the United States
collected and reported by the police to Federal Bureau of Investigation since 1930
highlights Part I or Index OffensesThe Crime Index
Murder, Rape, Robbery, Assault, Burglary, Larceny-Theft, Motor Vehicle Theft, Arson
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Reported Crimes, 1996
7.4 36.1 202.4388.2
943
2975.9
525.9
0
500
1000
1500
2000
2500
3000
MurderRape
RobberyAssaultBurglaryLarcenyVehicleTheft
Part I Crimes per 100,000
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Limitations of the UCROnly reflects the volume of crime
reported to the policeAffected by the recording practices
of the policeEmphasizes street crime. No
statistics on white-collar crimeFigures reflect the style of of police
work
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Strengths of the UCRThe major source of crime
statistics in the USPolice and citizens agree on
what constitute a serious crime“Unfounding”: how the UCR
verifies the data
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National Crime Victimization Survey
Conducted by the Bureau of Justice Statistics since 1972, the NCVSattempts to uncover unreported
crime; surveys 60,000 households.takes information directly from victimscollects background information on
victims
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UCR & NCVS CrimeType of Crime UCR NCVS
Rape 95,770 98,000
Robbery 537,050 1,134,000
Assault 1,029,810 1,910,000
Burglary 2,501,500 4,845,000
Larceny-Theft 7,894,600 21,120,000
Motor Vehicle Theft
1,395,200 1,387,000
TOTALS 13,453,930 30,494,000
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NCVS Rates, 1996
0.45.2
35.4
47.2
205.7
7.7
0
50
100
150
200
250
Rape Robbery Assault Burglary Larceny-Theft Motor Vehicle Theft
© 2001 Vito & Blankenship
Limitations of the NCVSAccuracy: Forgetting and “telescoping”
are potential problemsLying: Concealing victimizations due to
embarrassment or overreporting to please the interviewer
Asks questions about rape in an indirect manner
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Limitations of the NCVSProblems in administration and codingSurvey represents nation as a whole,
does not contain specific information on one area
Tends to overrepresent non-serious crime
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Why Crime Not ReportedReasons for not reporting crime
Violent crimespersonal or private matter and the offender was not successful
Theftproperty recovered, offender not successful, reported to some other official, lack of proof.household crimes: same as theft, plus police would not want to be bothered.
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Why Report Crime?
Violent Crimesto prevent future crimes by the
offenderto stop or prevent the crimebecause it is serious
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Why Report Crime?
Theftto recover stolen propertybecause it was a crimeto collect insuranceto stop or prevent the incident
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Advantages of CFS DataGatekeeping procedures of the police
are bypassed. Computers record every call
Interviewer, sampling and memory bias are not a problem
Police arrest statistics are often biased by place and status of the offender
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Weaknesses of CFS DataA complaint must be made
before it can be recorded by the system
Overreporting can occurOffense location not always
included
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Routine Activities TheoryElements of Routine Activities Theory: A motivated offender; A suitable target; The absence of a capable guardian to
prevent crime Crime control
prevent convergence of offenders and targets without guardians
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The Compstat Process
Accurate and timely informationWhat type of crime is it?Where is crime occurring?When is crime happening?Why is crime happening?
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Rapid deployment of resourcesEffective tacticsRelentless follow-up and
assessment
The Compstat Process
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Results
The Compstat Process leads to:enforcement strategies to target
specific crimes or conditionsRefocusing the strategy of community
policing giving Precinct Commanders
authority and responsibility
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Crime Reported to NYPDType of Crime
1996 1997 % Change
Murder 984 767 - 22.1%
Rape 2888 2788 - 3.6%
Robbery 49324 44339 - 10.1%
Assault 30615 30259 - 1.2%
Burglary 61986 54860 - 11.5%
Grand Larceny
58690 55670 - 5.2%
Auto Theft 59465 51330 - 13.7%
TOTAL 263,952 240,013 - 9.1%
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Misuse of Data
Steps to prevent misuse of crime statisticsobtain data over as many data
points and years as is feasibleincrease the number of indicatorsuse current data
© 2001 Vito & Blankenship
SummaryImportant to understand
limitations of researchStatistics can provide basis for
rational decision making ifvalidrelaible
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