Police data only part of the picture

Congratulations to the Herald data team for visualising police-recorded crime statistics so well.

If you were to look at the reported results from the New Zealand Crime and Safety Survey (NZCASS), , you would find out the following:

Only 20 per cent of crimes reported in this large representative survey actually end up in the police-recorded figures you use for your series.

Only 10 per cent of these incidents involve burglary, despite the media coverage. Half are related to violence or the threat of violence.

The survey provides a population base. For your figures we do not know whether the base for an area is 10,000 or 100,000.

Three per cent of the population experience 50 per cent of the crime.

In the last 10 years household crime has halved and personal crime was down by a third.

In other words, police statistics are only part of the picture. What NZCASS shows is that a tiny percentage of the population suffer most of the crime (why not some predictive policing?), and that crime is on a steep decline (why are we planning to spend a billion dollars on new prisons?).

The Herald series is great, but its reliance on police recorded statistics could reinforce a certain narrative around crime and punishment. Peter Davis, COMPASS Research Centre

University of Auckland