Using the Offenders Index to investigate patterns of offending

The Offenders Index is a rich data source which consists of criminal conviction information collected from the courts. While it has been used to identify, for example, the proportions of particular birth years which have had a criminal conviction, there has been little interest in how the types of offences which offenders are convicted change over time.
In this talk, we describe the problem of identifying patterns of offending behaviour, with the aim of identifying criminal lifestyles and how these might change over time. A latent class approach provides the methodological basis, and allows us to identify group profiles and the likely number of groups. While many offending patterns appear to be single offence, other offenders are involved in a mix of activity, some involving violence and others not. We observe strong changes over time and across birth cohorts, with the proportion of female offenders brought before the courts rising dramatically in later cohorts. While procedural changes offer some explanation of these
results, social change will also play a part.