2 Guide to using this report

2.1 Snapshot and throughput perspectives

Information is presented both as a snapshot (moment in time) view, and annual throughput. The snapshot shows the offender sub-populations at 30 June in any given year, with comparable monthly figures providing longitudinal context.

The throughput shows offenders as they transition on to new sentences and orders managed by the Department of Corrections in the context of historical trends.

The information is disaggregated by age, gender, ethnicity, the types of offences, sentence length, and other variables of interest.

2.2 Data set and methodology

The data set behind the report uses the most significant, or prevailing, directive issued by the Courts or by the New Zealand Parole Board to the Department of Corrections, in relation to individual offenders. For example, if a directive requires that an offender is sentenced to prison and no order applies indicating that he/she is to be released on or before a particular day, then the offender is counted as prison sentenced on that day1. Note that the data set does not include fines, conviction with discharge, or other sentences not requiring management by the Department.

Although the original source data is substantially the same as that for other published reports, it provides counts of transitions between different states of correctional management rather than simple counts of new sentence starts (see chapter 12 Data definitions and groupings for details).

It should be noted, when comparing this report and the 2009 report, some discontinuities emerge, largely because of improvements to the quality of the data in the latest report.

2.3 Glossary of terms

Where applicable, hyperlinks to the definitions and the glossary of terms (chapter 12 Data definitions and groupings) are provided below the figures. 

2.4 Graphical reporting supported by hyperlinked data spreadsheets

The figures show the trends in the volumes of offenders managed over time. Hyperlinks to spreadsheets containing the underlying data are provided below the figures.

2.5 Inventory approach

An inventory approach simplifies the presentation: each offender is counted only in a single management category, on any one day. The data summary in Chapter 10 Offender Inventory is provided in a form analogous to financial accounting. Offender flows and balances in the various management categories are detailed.

2.6 Target audience

The report is aimed at people with an interest in trends in the volumes of offenders in New Zealand.

1 The term sentenced muster is not used in this report as this term has a specific and different meaning in other contexts (generally referring to counts of sentenced prisoners physically present on a prison site on a day). However, prison sentenced offenders may not actually be on site due to hospitalisation, movement to a psychiatric facility, temporary release, escape, missing data etc