Reported crime numbers are only part of the story of crime and surveys paint a more reliable but less regular picture.
Police release several different data reports online each month, each providing a specific and partial view of the data.
Mitchell can request any data extract he wants from police, while the rest of us – including the opposition – have to rely on publicly-available data, or wait for responses to written parliamentary questions or official information act requests.
The Herald understands Mitchell was given monthly data on the number of reported “acts intended to cause injury” – or what the rest of us would call assaults – in the Auckland Police District.”
“Acts intended to cause injury” includes common assault, serious assault not resulting in injury, and serious assault resulting in injury – see below for full definitions.
The minister’s statements
In a release on Sunday, September 15, Mitchell said: “Police data shows that from January 1 to July 31 this year, there was a 22% reduction in serious assaults within the Auckland CBD compared with the same period last year, and an 18% reduction in serious assaults resulting in injury.”
The total number of serious assaults in the CBD dropped from 466 in the first seven months of 2023 to 365 in the first seven months of this year – a 22% decrease. Serious assaults resulting in injury dropped from 297 to 245 – or 18%.
The minister chose not to mention the 3% increase in common assaults – from 497 to 512. In response to a Herald query he acknowledged common assaults had increased and said: “There are any number of statistics that we could have included or excluded, the reality is that this was to share the news that the most violent of assaults – something I am regularly told has been a problem in Auckland – are dropping.”
What about the rest of Auckland?
It is natural to wonder whether Mitchell’s figures reflect an actual decrease in crime, or whether criminal behaviour has just been exported from the CBD to other parts of Auckland.
Data is publicly available on the total number of serious assaults reported up until the end of July 2024. This data is essentially the same as the figures police provided to Mitchell but the geographic breakdowns are only for police districts, which do not match Auckland’s actual boundaries.
This data shows serious assaults dropped in all three Auckland police districts and fell by 3.1% overall.
This doesn’t support Andersen’s claim that serious assaults were exported from the CBD to the rest of Auckland.
Labour’s data
Andersen used the only public dataset with CBD-specific data. However, in this data residential assaults are excluded. Residential assaults make up about 70% of reported serious assaults.
This is a sobering reminder of how many assaults occur in people’s homes.
The assaults in public statistics shouldn’t be used in comparison to the minister’s data as it is essentially a different dataset.
But it could be argued that looking at “assaults in public” is a better indicator of the impact of deploying more beat staff.
The total number of serious assaults in public dropped by 85, or 25%, in the CBD – a bigger drop in the CBD than the 22% announced by the minister.
But in the rest of Auckland, serious assaults in public increased by 356, or 15%. With the number of incidents for the increase more than those for the decrease in the CBD, it suggests a range of issues are driving the change in assault numbers.
What can we say?
Serious assaults in the CBD did drop by 22% when comparing this year with the first seven months of last year. But when common assault is added to the total the decrease is a more modest 9%. At the same time, serious assaults across all of Auckland fell by about 3%.
Serious assaults in public in the CBD dropped more, but increased in the rest of Auckland. The data is consistent with the shifting of crime from the CBD, but it cannot tell us what was behind the increase in serious assaults in the rest of Auckland. That would require a more detailed analysis by police.
Definitions
Unless otherwise stated, all comparisons between 2023 and 2024 in this article refer to the first seven months of each year.
According to the Australian and New Zealand Standard Offence Classification (ANZSOC) definition:
- a “serious assault resulting in injury” is the direct and immediate infliction of force, injury or violence upon a person or persons resulting in an injury. For this purpose, injury includes grievous bodily harm, actual bodily harm, wounding, severe mental behavioural disturbance or disorder, or loss of a foetus.
- a “serious assault not resulting in injury” is the same without an injury, but includes assaults committed in company, the use of a weapon, committed against a vulnerable victim, pregnant person, prison officer, police officer or other justice official, involving more than one victim, part of planned or organised criminal activity or any aggravating circumstance specified by criminal legislation.
- a “common assault” is any assault that does not meet that threshold (ie, there is no injury and it does not meet the threshold of serious assault not resulting in injury).
- “Assault” is serious assaults and common assaults combined.
