Data presented here has been simplified and categorised for analysis of high-level statistics. It is compiled from the criminal courts' operational data. Like all operational data it contains some anomalies which do not affect its day-to-day use. However, anomalies have potential to be a source of error in this statistical data.
For example, incorrect coding of some data items, while having no impact on the progression of charges or cases through the court system, can impact how the data is categorised and counted when reporting statistical summaries.
Nonetheless, the effect of such anomalies is minimal. There are rigorous processes in place to verify and ensure the accuracy of data recorded for operational purposes. The result is that datasets are sufficient for the purpose of illustrating the trends in prosecutions, convictions, and sentencing over time.
Some notes on particular data quality issues are given below.
Demographic information
The information on the gender, ethnicity, and age of offenders presented in the convicted offender tables is usually recorded by the prosecuting authority (mostly the police) at, for instance, the time of arrest. Data on the gender and date of birth (used to calculate the age) of offenders are generally accurate.
Re-sentencing after non-payment of fines or reparation
Offenders who default in the payment of their fine or reparation sentence can be re-sentenced by a judge to imprisonment or community work (and before the Sentencing Act 2002 came into force also corrective training, periodic detention, or community service).
Re-sentencing for community-based sentences
Offenders sentenced to a community-based sentence can, under certain circumstances have their sentence reviewed. This sometimes results in another (possibly more serious) sentence being imposed.
Enforcement of suspended sentences
Prior to the sentence’s abolition in mid-2002, people who had a suspended sentence of imprisonment imposed could have the sentence activated because of a subsequent conviction within the suspension period. The activation of suspended prison sentences was not usually recorded in the data used for these tables.
Fines
Only court-imposed fines are included in the tables. Fines resulting from the issue of an infringement notice (such as speeding or parking offences) are not included in the data.
Affect of appeals
Data from the previous two years should be considered provisional as appeals can influence charge outcomes and sentences. Any comparison between previous versions of the conviction and sentencing tables can show these differences. However, re-sentencing data needs to be treated with caution as it may not have been reported in all cases.
For more details on these issues see Chapter 1 of the Conviction and Sentencing of Offenders in New Zealand: 1997 to 2006 report.