Scottish Prison Population Statistics, 2020-21

Introduction

An Official Statistics Publication by Scottish Government Justice Analytical Services on behalf of the Scottish Prison Service

About Scottish Prison Population Statistics

This publication was produced by Scottish Government statisticians using administrative data from the Scottish Prison Service (SPS) management information system PR2. These data are collected by prison officers and staff for operational intelligence and logistical support.

It is important to note that the prison population is not static; individuals move in and out of the population every day. PR2 is a live system, updating constantly to capture changes to the state of the prison population. An extract of data from this system reports on the population at the moment in time the extract is drawn. Like many other operational databases, it was not designed to retain detailed historical data, or to provide retrospective information to assess how the prison population has changed over time.

Up until 2014, the Scottish Government held and reported on data compiled by combining and linking daily extracts from PR2. A number of the tables and figures in those previous reports were also based on single-day ‘snapshots’ rather than the data compiled throughout the year.

Due to technological changes in 2014, it is no longer possible to produce these data. The dataset used in this pubication has been created using the the information that still exists about the times when prisoners occupied specific cells. Hence the population spine underlying this publication is termed “Cellwise”, or the Cellwise data. More detail on how these data are constructed is provided in the Technical Manual^[4].

The construction of the Cellwise data is fundamentally different, both to the previous data design and to the aggregation produced by SPS in the interim. It has therefore not been possible to align these results exactly with previous publications. Chapter 7 shows that trends and approximate levels are sufficiently aligned for meaningful interpretation of high level prison population trends. Uncertainties in certain metrics will be highlighted throughout this report, and are also listed in chapter 7.

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