Transcript Crime Statistics, Information Sources and Research

How do we analyse crime
statistics?
Lucy Snowball
NSW Bureau of Crime Statistics and Research
About me
• Bachelor of Arts/Commerce
– Statistics, maths and economics
• Statistician at the Bureau of Crime Statistics and
Research
– Use statistical methods to analyse crime and offending
patterns
About BOCSAR
• Data from police and court records
• Types of research
– Who gets sentenced to prison?
– Juvenile offending
– Social and economic factors that affect involvement in
crime
– Predict re-offending
Methods we use
• Summary statistics
– Mean, standard deviation, median, mode, range
• Time series analysis
– Increasing/decreasing trends
– Break points
• Regression modelling
– Building an equation to see which factors influence
others
Factors to consider
• How is the offence recorded?
• Which groups are most likely to commit
this offence (young people, men, people in
cities)
• What effect will policing policies have?
• What external factors might affect rates
– The economy, government policies, commercial
decisions, other crime rates
Example: Narcotics use
• Heroin is the most common narcotic
• Police record each time they arrest a person for use
or possession of a narcotic
• Offenders: young people (18-30), people in major
cities (Sydney, Newcastle, Wollongong)
• The time series can reflect actual use or policing
strategies
• All drug use is affected by the availability of that
drug
• Effects other crimes - Narcotics linked to property
crime