Is the Crime Drop in Scotland Due to Changes in Prevalence or Frequency?: A Decomposition Approach

• In Event: International Perspectives on Crime, Violence, and Victimization Over the Life-Course

Abstract

Changes in crime rates can be split into three factors: change due to the number of people who offend (prevalence), change in the rate of offending by those who do offend (frequency) and demographic change. Using the methods of standardization and decomposition common in demography, change in the total convictions rates in Scotland over the course of the recent crime drop (1989-2011) is divided into contributions from these three factors. Results suggest that prevalence has played a greater role than frequency in leading to declining convictions rates, but also that there are important differences in the relationship between prevalence and frequency for people of different ages, between men and women and over time. Overall declines in convictions over the period of the crime drop are driven by lower rates of convicted offences for young people, whilst those between 25 and 40 show aggregate increases in convictions rates over this period. Explanations for the crime drop in Scotland must be able to account for these differences.

Author

• Ben Matthews, University of Edinburgh