Which is the most violent country?
Murders/year
15,434
1785
Estonia (1994)
423
Japan (1994)
England & Wales (1997)
770
725
Figures based on data obtained from http://www.guncite.com/gun_control_gcgvinco.html
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United States (1999)
Taiwan (1996)
Which is the most violent country?
United States (1999)
Taiwan (1996)
5.70
8.12
Estonia (1994)
28.21
Japan (1994)
England & Wales (1997)
0.62
1.41
Crime numbers do not permit comparisons between
places or over time. Crime rates (the number of crimes
per unit of population per year) do.
Figures based on data obtained from http://www.guncite.com/gun_control_gcgvinco.html
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Annual Murders/100,000 pop.
Today’s session
You are learning to...
• Assess the validity of
measurements
• Identify factors that can
distort measurements
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You are learning about...
• Measuring crime
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• Why would we want to know how much crime
there is?
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• The Republic of Elbonia is a newly created
nation. Like most nations, they have a
government, a civil service, a judicial system
and a police force. They want to be able to
keep track of how much crime occurs in their
country and have asked for your help. How
would you measure crime in Elbonia?
Ways of measuring crime
• Official statistics
– Crimes reported to the police
– Court & prison statistics
• General population surveys
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– Victimisation surveys
– Offender surveys
Possibly
criminal act
Police
attention
Noticed by
public
Designated a
crime by police
Designated a
crime by public
Recorded as a
crime
In what ways might this process produce an inaccurate
account of the crime rate?
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Police statistics
Court & prison statistics
• In which ways might the true extent of crime
be distorted by looking at:
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– The numbers of people convicted of various types
of offence?
– The numbers of people imprisoned for various
types of offence?
General population surveys
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• In which ways might the British Crime Survey
be a more and a less valid measure of crime
than police statistics?
• Why might a general population offender
survey underestimate the extent of more
serious crimes?
General issues
– Each offers a different perspective on crime rates
– Different measures have different uses
– Measures can be triangulated
– Problem is not the data but their interpretation
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• Crime data, like most psychological data, are
of ‘limited usefulness in limited circumstances’
(Howitt, 2009; p.21)
General issues
• There is a ‘dark figure’ of unreported and
unrecorded crime
• Generally, the more serious crimes are more
likely to be noticed & reported, so much of the
dark figure is less serious crimes
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– Which types of crime do you think are most likely
to make up the ‘dark figure’?