This lecture Measuring Crimes" is taken from the subject Forensic Psychology.

1. Chapter 2 – The Nature and
Extent of Crime

2. Crime Patterns and Trends
 Want to know
 How much crime is there?
 Is it increasing or decreasing?
 Who commits crime?
 Answers are used to formulate theories
and develop policies to control crime

3. Methods of Measuring Crime
Uniform Crime Reports
Victim Surveys
Self-Report Surveys

4. Uniform Crime Reports
 Best known source of aggregate
criminal statistics
 98% of the police departments in the
US voluntarily participate in UCR
 Yearly FBI publication
 Started 1930

5. Uniform Crime Reports
 2 types of data collected:
 1) Offenses reported to the police
 Collect information on index crimes
reported to the police
 Known as Index or Part I crimes

6. Uniform Crime Reports
 Index Crimes
 Criminal Homicide
 Forcible Rape
 Robbery
 Aggravated assault
 Burglary
 Larceny/theft
 Motor vehicle theft
 Arson
Violent
Crime
Non-violent
Crime

7. Uniform Crime Reports
 2) Number and characteristics (age,
gender, and race/ethnicity) of those
arrested for all other crimes
 Known as non-index or Part II crimes
 On average, 20% of all reported index
crimes are cleared by arrest, lower for
many non-index crimes.

8. 69%
50%
28%
19%
14% 14%
0%
20%
40%
60%
80%
100%
Percent of Crimes Cleared by Arrest
murder
rape
robbery
larceny
burglary
MVT

10. Uniform Crime Reports
 Problems with the UCR
 1) On average approximately 50% of all
index crimes are reported to the police
 26% of thefts
 50% of burglaries
 45% of rapes
 57% of robberies

11. Uniform Crime Reports
 2) On average, 20% of all reported
index crimes are cleared by arrest
 3) State law definitions may be different
than UCR definitions
 4) Systematic errors in reporting
 5) Deliberate alteration

12. Uniform Crime Reports
• 6) Only the most serious crime is an
“episode”
• 7) Weak on “white collar” crime

13. The Future of the Uniform Crime
Reports
 National Incident-Based Reporting
System (NIBRS)
 Maintained by the F.B.I.
 Twenty-two crime categories
 More information on each crime in each
category
 Data compiled based on incidents, not
arrests.

14. Victimization surveys
 National Crime Victimization Survey-NCVS
 US Census
 Started in 1972
 60,000 households
 120,000 people over 12 years old
 Interviewed 2 times a year for 3 years

15. NCVS
 Ask about theft, burglary, robbery,
assault, rape, and auto theft
 Used to estimate the national frequency
of index crimes

16. Data provided by NCVS
 Victimizations
 Victims, offenders, crime event
 Reported loss & injury
 Whether crimes were reported

17. NCVS
Source: National Crime Victimization Survey. Criminal Victimization, 1997. Adapted from U.S.
Department of Justice, Bureau of Justice Statistics (Washington, DC: U.S. Government Printing
Office, December 1998), p. 3.
*Includes 357,000 “personal crimes” of purse snatching & pocket
picking.
Number of Offenses
20,106,000
7,359,000
4,635,000
1,433,000 944,000
311,000
Theft* Assault Burglary Motor vehicle
theft
Robbery Rape/ Sexual
assault
Total = 35,145,000

18. Advantages & Limitations of NCVS
ADVANTAGES
1) Best victimization data
2) “larger picture of crime”
DISADVANTAGES
1) Victim
misinterpretation
2) Memories fade
3) Lying to interviewer
4) Telescoping – problems
with recall
5) Expensive

19. Self-Report Surveys
 Participants reveal information about their
violations of the law
 Helps to get at “Dark Figure of Crime”
 Supplement and expand official data
 Can find out about the personality, attitudes,
and behavior of criminals
 Accuracy for chronic offenders and drug
abusers may be limited

20. Self Report Studies
 Interviews mainly with juveniles
 Most youth engaged in delinquency (crime
is universal
 Higher crime patterns than UCR and NCVS

21. Self-Report Surveys
 Strength of self-reports surveys is get
more detailed information
 Weaknesses include
 Inaccuracy – are they telling the truth?
 Focus on trivial acts frequently

22. Current Crime Trends
Current data from the Uniform
Crime Reports and the National
Crime Victim Surveys reveal a
steady decrease in crime. Self-
reported data reveals no
discernable change in the rate.

23. Current Crime Trends
 Caution in interpreting UCR and other
data
 Time frame is important
 Overall rate hides increases and
decreases within crime categories
 Want disaggregated data
 By offense, state/region, etc.

24. Explaining Crime Trends
 Age
 The economy
 Guns
 Gangs
 Drugs
 Justice Policy
Some of the important
critical factors that have
been used to explain the
puzzle of crime rate trends.

25. Correlates of Crime
• Age
• Gender
• Race
• Social class

26. Correlates of Crime –
Social Class
 Higher crime rates in lower class areas
 Rely on official statistics
 Concern over whether function of police
practices or actual behavior patterns
 Crime is not just street crime
 Self-report studies indicate class-crime
relationship doesn’t exist
 Focus on trivial offenses

27. Correlates of Crime –
Social Class
 Why important?
 1) If class-crime relationship then
poverty and neighborhood deterioration
related to crime
 2) If not then factors experienced by all
classes (poor family environment, peer
pressure, school failure, free will)
related to crime

28. Correlates of Crime –
Age
 Some argue that age structure of
society is the single most powerful
influence on the crime rate
 13-17 year olds make up 6% of the
population but 30% of index crime
arrests

29. Correlates of Crime –
Age
 Property crime arrests peak at age 16
 Violent crime arrests peak at age 18

30. Correlates of Crime –
Age
 Why does aging out occur?
 Cognitive changes in late teens
 No longer need for immediate gratification
 Fear of punishment
 Adulthood brings powerful ties to
conventional society

31. Correlates of Crime –
Gender
 Male crime rate higher than female
 Males commit more serious crimes
 Recent view of female criminality
 Socialization of females (supervised
closely)
 Changing social and economic role of
women

32. Correlates of Crime –
Gender
 Crime more a function of economic
inequality instead of female rights
 End of “chivalry hypothesis”

33. Correlates of Crime –
Race/Ethnicity
 Minorities involved in disproportionate
% of crimes
 Blacks 12% of population, 44% of index
violent crime arrests
 Reflection of police practices or true
criminal participation?

34. Correlates of Crime –
Race/Ethnicity
 Causes of racial disparity in crime
 Differential treatment by police
 Subculture of violence
 Racism and discrimination affect
personality and behavior
 Poverty/Urban problems
 Etc.

35. Knowledge drawn from UCR,
NCVS, and Self Report Studies
 Crime Trends
 Characteristics of Crimes
 Characteristics of offenders & victims
 Correlates of Crime

36. After following a birth cohort of 9,945 boys
born in Philadelphia in 1945, Wolfgang and
his associates found that 6% of the total sample
were responsible for 51.9% of all offenses.
The “Chronic 6%”

37. The “Chronic 6%”
 Wolfgang findings
 1) Small number of offenders commit a
disproportionate amount of crime
 2) Chronic offenders continue into
adulthood
 3) More violent as generations progress