1504.0 - Methodological News, Jun 2001  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 21/07/2001   
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These projects are part of a set of projects being done jointly with the National Centre for Crime and Justice Statistics (NCCJS) and the Australian Institute of Criminology (AIC). They use the 1998 National Crime and Safety Survey to:

  • develop small area estimates of crime; and
  • estimate the propensity of different groups to report crime to the Police.

Both projects use regression methods to analyse the 1998 National Crime and Safety Survey (1998 NC&SS) unit record file.

The "small area estimates of crime" model estimates a regression associating crime rates from the 1998 NC&SS, with socio-demographic data from the 1996 Census. This model is estimated for statistical regions. The coefficients derived are then applied to Statistical Local Areas (SLA), to derive estimates of crime by SLA. The assumption implicit in this is that the characteristics of crime-prone communities at the statistical region are the same as they are at the SLA level. This technique is called synthetic estimation in the literature.

The "propensity to report crime" model uses logistic regression to estimate the propensity to report crime to the Police. The Yes/No reporting behaviour is modelled against victim characteristics from the 1998 NC&SS. The model is estimated using the 1998 NC&SS unit record file.

The outcome of the projects is of particular interest for criminologists and practitioners in the justice field. In particular, there has been considerable interest from Police and the Departments of Justice in each State.

Both models will be validated using sensitivity analysis, and, where definitions have not changed much, the 1993 National Crime and Safety Survey.

Some additional issues are being addressed in this work, such as:
  • how to apply regression models to complicated sample designs; and
  • how to use small area estimation techniques to get reliable estimates for small areas without increasing the sample size.

We are taking into the account sample design in a number of ways, and will compare the different results. The two broad ways we are taking sample design into account is using the survey weights in some way, and using replicate weights.

The project team is Robert Tanton and René Jones.

For more information, please contact Robert Tanton on (02) 6252 5506

E-mail: robert.tanton@abs.gov.au