## How The Measure Of Proven Reoffending Has Changed And The Effect Of These Changes

 
26th October 2017 

## How The Measure Of Proven Reoffending Has Changed Background In "Transforming Rehabilitation: A Strategy For Reform", Published In 2013, Plans Were Set Out To Introduce A New System For The Management And Rehabilitation Of Offenders In The Community Across England And Wales.

In February 2015, various reforms were implemented. These included:   

- 
opening up the market to a diverse range of rehabilitation providers from the private, voluntary 
and social sectors through 21 Community Rehabilitation Companies (CRCs); - 
using a 'payment by results' approach to develop and implement effective ways of rehabilitating 
offenders and rewarding providers that devise and deliver the most effective rehabilitation 
programmes; - 
extending statutory rehabilitation to short-sentenced offenders released from prison, who have 
the highest reoffending rates and yet previously received no supervision after release; - 
reorganising the prisons to resettle offenders 'through the gate', with continuous support from 
custody to community; and - 
creating a new public sector National Probation Service (NPS) to manage high risk offenders. 
 
Following implementation of these reforms, a public consultation was run in summer 2015, proposing several changes to the Proven Reoffending National Statistics in order to support the reforms to the system and ensure the Ministry of Justice continued to meet its commitment of statistical best practice by giving a coherent overview of all statistics relating to reoffending.  

 
Users' views were invited to the proposed changes, and 19 responses were received to the consultation. A response to the consultation was published in April 2016 and set out the changes: www.gov.uk/government/uploads/system/uploads/attachment_data/file/519644/proven-reoffendingconsultation-response.pdf 
 
The main changes to the methodology are: 

 
- **Moving to a three month cohort.** The latest publication reports on offenders who are released from 
custody, received a non-custodial conviction at court, or received a caution within a three month period, for all measures of reoffending, including for juveniles. Previously, a 12 month cohort was used. 
 
- Production of **adjusted reoffending rates for adults** (alongside the raw rates). The Offender Group 
Reconviction Score (OGRS) has been used to adjust the raw reoffending rates for adults, to take account of the influence that differences in offender mix can have on the binary reoffending rates.  
 
- **A change from calendar year to financial year, for annual figures.** Previously, the annual publication 
was in October each year, and based on a calendar year. The annual reoffending publication will now be published in January each year and will be based on a financial year. Annual figures will be formed by taking a weighted average of the four preceding 3 month offender cohorts. 2015 annual figures will be published on the 25th January 2018. 

## 

In addition, there is a change in the **data source** for compiling MoJ's proven reoffending statistics to better reflect the way in which offenders are now managed by the probation services. The data source is called national Delius (nDelius) and is the established case management system for use by probation services. nDelius has already been used to compile the published interim Payment by Result (PbR) figures for CRCs and the NPS since October 2016. The first set of proven reoffending statistics being published using the new methodology and data source are for the **October to December 2015** cohort. They are being published alongside the first set of final results for the Community Rehabilitation Companies (CRCs) and the National Probation Service (NPS). These are the results by which CRCs' performance will be assessed for PbR. 

The new approach creates **one consistent measure of proven reoffending** and allows users to relate the performance of the CRCs in reducing reoffending with the overall figure for England and Wales. 

 

## The Impact Of The Changes

For adult and juvenile offenders, the new measure is based on all offenders released from custody, receiving a non-custodial conviction at court or receiving a caution within a 3 month period (Figure 1). The previous measure reported on adults and juvenile offenders within a 12 month period. Changing from 12 
month offender cohorts to 3 month offender cohorts results in a greater proportion of prolific offenders and hence higher reoffending rates. 

## Figure 1

 
Table 1 shows the proportion of offenders with a proven re-offence using the new measure of reoffending and the previous measure of reoffending. The first columns compare the latest annual figures (for April 2014 to March 2015) using the previous measure based on a 12 month cohort and the new measure based on a weighted average of the four preceding 3 month cohorts. It can be seen that reoffending rates are around 4-5 percentage points higher using the new method, for both adult and juvenile offenders than the previous method. 

| New                                              | Previous    |
|--------------------------------------------------|-------------|
| annual                                           | 12 month    |
|                                                  |             |
| average                                          | cohort      |
| Apr                                              |             |
| 2014-                                            |             |
| Mar                                              | Apr 2014-   |
|                                                  | 2015        |
| 1                                                |             |
|                                                  |             |
| Adult offenders                                  |             |
|                                                  |             |
| Proportion of offenders who reoffend (%)         |             |
| 28.9                                             | 24.3        |
| Adjusted                                         |             |
| 2011                                             |             |
| proportion of offenders who reoffend (%)         |             |
| 28.6                                             | -           |
| Average OGRS4/G score                            | 33.7        |
| Average number of reoffences per reoffender      | 3.68        |
| Number of reoffences                             | 544,719     |
| Number of reoffenders                            | 148,130     |
| Number of offenders in cohort                    | 512,684     |
| Average number of previous offences per offender | 17.64       |
|                                                  |             |
|                                                  |             |
|                                                  |             |
| Juvenile offenders                               |             |
|                                                  |             |
| Proportion of offenders who reoffend (%)         |             |
| 42.6                                             | 37.9        |
| Average number of reoffences per reoffender      | 3.61        |
| Number of reoffences                             | 69,319      |
| Number of reoffenders                            | 19,186      |
| Number of offenders in cohort                    | 45,042      |
| Average number of previous offences per offender | 3.56        |
|                                                  |             |
| All offenders                                    |             |
|                                                  |             |
| Proportion of offenders who reoffend (%)         |             |
| 30.0                                             | 25.3        |
| Average number of reoffences per reoffender      | 3.67        |
| Number of reoffences                             | 614,038     |
| Number of reoffenders                            | 167,316     |
| Number of offenders in cohort                    | 557,726     |
| Average number of previous offences per offender | 16.50       |
|                                                  |             |

In addition to the change in cohort, in October 2015 there is also a change in the data source used to compile the statistics (see Annex A). Proven reoffending statistics have, until now, been based upon information drawn from the Inmate Information System to identify those offenders discharged from custody. For the latest proven reoffending statistics, custodial discharges have been taken from the national Delius system for adults and from the Prison-Nomis system for juveniles. The reason for changing to nDelius is to ensure the proven reoffending statistics align with reoffending statistics produced for the Community Rehabilitation Companies, and because nDelius has become the main system for managing the flow of adult offenders. As juveniles are not managed by the probation system in the same way as adults, 
1 Users should not compare the October to December 2015 cohort with previous cohorts, due to a change in data source and potential variability.  
 
offenders discharged from Youth Offender Institutions are now taken from the Prison-Nomis system. The change for juveniles also reflects the availability of a more accurate data source. This change in October 2015 introduces potential variability and therefore users should be cautious when making any comparison with the October to December 2015 cohort and earlier cohorts. It is estimated the impact of changing data source is an increase in the reoffending rate of around 0.5 percentage points. The driver for this increase appears to be among offenders discharged from custody after serving less than 12 month sentences, and might be connected to the introduction of statutory supervision for this group. Further investigation is ongoing. The impact of changing data source for juveniles discharged from Youth Offenders Institutions is marginal.   

## Trends Over Time Despite The Increase In The Reoffending Rate, Both Measures Show Similar Trends Over Time. The Adult Proven Reoffending Rate Has Remained Fairly Flat Over Time (Figure 2), Fluctuating Between 28% And 31%. Among Juveniles There Has Been An Increase In The Proven Reoffending Rate Since 2005 Of Around 4 Percentage Points, Using Both Methodologies. However, The Size Of The Offender Cohort Has Reduced Considerably For Juveniles Over The Same Period.

 There is also a similar trend in the proven reoffending rate when comparing by index disposal (Figure 3), with the adult proven reoffending rate for custody and court orders now around the lowest level since 2005. 



Although the trend is broadly the same by disposal, there is an impact on the October to December 2015 cohort from changing data source. This is particularly noticeable among offenders discharged from custody, and within that the biggest impact is among the less than 12 months custodial sentence length group. This might be connected to the introduction of statutory supervision for this group and a data source which tracks offenders better; and further investigation is ongoing. Adult adjusted reoffending rate: 
The Offender Group Reconviction Scale (OGRS4/G) is used to control for some differences in offender characteristics across different offender groups. OGRS4/G uses age, gender and criminal history to assess the reoffending risk of a given group of offenders by producing a score between 0 and 1. A higher score means an offender is more likely to reoffend.   
The reoffending rates are adjusted to 2011 in line with Payment by Result statistics. In the example below, we would say that the proven reoffending rate for the period April 2014 to March 2015 has reduced since 2011. However, the average OGRS score has increased, meaning that the cohort of offenders is more likely to reoffend. As a result, when we control for changes in offender characteristics the adjusted reoffending rate fell by 1.6 percentage points since 2011. 

 

## Ogrs4/G Adjusted Reoffending Rate For Adults Example

| England and Wales    |   2011 comparison year  | Cohort period (April    | Difference       |
|----------------------|-------------------------|-------------------------|------------------|
| to March 2015)       |                         |                         |                  |
| 33.4                 |                    33.7 | +0.3                    |                  |
| Average OGRS4/G      |                         |                         |                  |
| score                |                         |                         |                  |
| 30.2                 |                    28.9 | -1.3pp                  | Proportion of    |
| offenders who        |                         |                         |                  |
| reoffend (%)         |                         |                         |                  |
| 30.2                 |                    28.6 | -1.6pp                  | OGRS4/G adjusted |
| reoffending rate (%) |                         |                         |                  |

 In the latest publication, the raw reoffending rates have been adjusted using OGRS4 to take account of the influence that differences in offender mix have on the binary reoffending rate. Between 2005 and 2011, the average OGRS score increased, but since 2011 it has remained broadly flat (Figure 4). This suggests that between 2005 and 2011 the cohort had an increasing propensity to reoffend, but this has since levelled off. As a result, the raw reoffending rate for adults is adjusted upwards between 2005 and 2011, reflecting the cohort having a greater propensity to reoffend. Since 2011, the raw rates and the adjusted rates have tracked each other more closely. For example, the raw reoffending rate for adults for the October 2014 to September 2015 period was 28.4%, but the adjusted rate was 28.3%. 

When looking at adult reoffending rates by index disposal, there has been a slight decline in the average OGRS scores since 2011 for custody and court orders (Figure 5). This reflects that the cohort is less likely to reoffend and therefore the adjusted rate is slightly higher than the raw rate. This is similar to the trend we see for Community Rehabilitation Companies. To date, it has not been possible to produce an adjusted reoffending rate for juveniles, but work in this area is ongoing.  
 

## The Change In Methodology

The following section provides detail regarding the change in methodology, data sources and the geographical breakdowns available. The tables below provide a comparison of the previous methodologies with the new approach. 

 
Previous measure of proven reoffending 
New measure of proven reoffending 
The cohort 
All offenders who were released from custody, received a noncustodial conviction at court, or received a caution within a *twelve* month period. 
All offenders who were released from custody, received a noncustodial conviction at court, or received a caution within a *three* month period. 
No change. 
The follow-up period to measure reoffending 
12 months for offences to occur and a further 6 months for offences to be proven in court. 
No change. 
What counts as a proven reoffence 
Offences committed within the follow-up period which were proved by a court conviction or caution/reprimand or final warning either within the one year followup period or in a further six months. 
Annual reoffending rates 
Annual figures based on a calendar year and published in October. 
Annual figures based on weighted average of 4 three month cohorts. Based on a financial year and published in January. 
Use of a predicted rate of reoffending 
None. 
Offender Group Reconviction Scale used to adjust raw adult rates of reoffending. 
 

## Change In Data Source: October 2015 Onwards

 
Previous measure of proven reoffending 
New measure of proven reoffending 
Inmate Information System 
National Delius 
Data source for adult custodial discharges  
Inmate Information System 
Prison-Nomis 
Data source for juvenile custodial discharges 

## Geographical Breakdown

 
Previous measure of proven reoffending 
Geographical data tool  
Contains data on the number of offenders in the cohort, reoffenders and reoffences by sex, age and index offence (excluding LTLA and YOTs) by:  

- 
England and Wales 
- 
Region 
- 
County 
- 
Upper Tier Local Authority (UTLA) 
- 
Lower Tier Local Authority (LTLA) 
- 
Youth Offending Team (YOT) 

This data was published based on 12 month cohort periods from 2005 onwards.  
Prison/Youth Secure Accommodation/Probation Region data tool 
This pivot table contains data on the number of offenders in cohort, reoffenders and reoffences by the following categories: 
- 
Type of custody by 
individual prison/youth offender institution/secure training centre/secure children's home and sentence length. 
- 
Probation region by sentence type. 
This data was published based on 12 month cohort periods from 2007 onwards. 
New measure of proven reoffending 
No change in breakdowns published in this data tool. Change in cohort periods provided in this data tool. The data is published using annual figures based on weighted average of 4 three month cohorts which are based on financial years from April 2005 to March 2015. From March 2015 
onwards, three month cohorts are published until a complete financial year is available (the next complete financial year will be available from January 2018). Prisons included in this data tool for all cohorts before October- December 2015 are based on prisons that were operating up to the end of September 2015. Data are missing for prisoners 
released from prisons in previous years that are no longer operational. Prisons data is only reported up until September 2015, due to data quality issues in the October to December 2015 cohort. Work is ongoing to improve data quality so that this can be produced in the future. Change in cohort periods provided in this data tool. The data is published using annual figures based on weighted average of 4 three month cohorts which are based on 

financial years from April 2005 to March 2015. From March 2015 onwards, three month cohorts are published until a complete financial year is available (the next complete financial year will be available from January 2018). 

## Contact

Press enquiries should be directed to the Ministry of Justice press office: 
Tel: 020 3334 3536 Email: newsdesk@justice.gsi.gov.uk  
Other enquiries about these statistics should be directed to the Justice Statistics Analytical Services division of the Ministry of Justice: 
Nick Mavron, Head of Prison, Probation, Reoffending and PbR Statistics Ministry of Justice, 7th Floor, 102 Petty France, London, SW1H 9AJ 
Email: Statistics.enquiries@justice.gsi.gov.uk 

## © Crown Copyright Produced By The Ministry Of Justice

Alternative formats are available on request from statistics.enquiries@justice.gsi.gov.uk

## Data Sources Pre-October 2017

Adult prison releases 
Adult prison releases 
(determinate). Inmate 
(indeterminate) PPUD
Information System
Cautions and out of 
Proven Reoffending 
court disposals for 
Measure Input data (pre 
| Adult court orders.    |
|------------------------|
| youths and adults.     |
| October 2017)          |
| PNC                    |
 Juvenile custodial 
Juvenile custodial 
releases from Secure 
releases from Youth 
| Children Home's and      | Offender Institutions.    |
|--------------------------|---------------------------|
| Secure Training Centres. | Inmate Information        |
eAsset system
System

## October 2017 And Beyond

| Adult prison releases    |  Juvenile custodial releases    |
|--------------------------|---------------------------------|
| (determinate and         | from Secure Children Home's     |
| indeterminate)           | and Secure Training Centres.    |
| Adult court orders.      | nDelius                         |
| Proven Reoffending       |                                 |
| Cautions and out of      | Measure Input data              |
| court disposals for      | (from October 2017)             |
| youths and adults.       | PNC                             |
| Juvenile custodial       |                                 |
| releases from Youth      |                                 |
| Offender Institutions.   |                                 |
| P-nomis                  |                                 |