Data First: Criminal Courts linked data – An analysis of returning defendants from 2011 to 2019 in England and Wales

Data First: Criminal Courts linked data – An analysis of returning defendants from 2011 to 2019 in England and Wales

Authors: Tom Jackson, Caris Greyson, Dr Ian Rickard (Ministry of Justice) and Professor Andromachi Tseloni (Nottingham Trent University)

Date: March  2022

Research summary

Research carried out by the Ministry of Justice has found that 56% of defendants returned to the courts between 2011 and 2019. This finding was highest for specific offence groups including theft, robbery, and drug offences. The researchers also carried out locality-based analysis on Crown Court defendants which highlighted an over-representation of defendants residing in the most deprived areas in England and Wales compared to the general population.

The Ministry of Justice’s pioneering data linking programme Data First, funded by ADR UK, links administrative datasets across the justice system.

The analysis has provided powerful new insights for policy and practice on repeat defendants, which have been shared with Ministers and policymakers. This is crucial for understanding how interventions can be targeted to reduce reoffending, a key departmental priority. Importantly, this research has also provided a foundational understanding of the potential of these datasets.

Data used

This research project links data from the following datasets:

The multi-disciplinary team across the Ministry of Justice worked collaboratively to map and scope the administrative data systems to produce these research-ready datasets. They can be accessed securely by accredited researchers via the Office for National Statistics (ONS) Secure Research Service.

The datasets have been de-identified, deduplicated and linked to provide a joined-up picture of criminal court defendant and case journeys through the courts. Ministry of Justice Data First data scientists created Splink – an award-winning method of record linking, in which an estimated unique defendant identifier (ID) was created (not previously available).

Additional data sources used:

Methods used

The analysis focused on descriptive statistics regarding the extent and nature of returns to the courts over a nine-year period, covering data from 2011 up to December 2019.

A defendant who entered the criminal courts on more than one occasion was defined as a returning defendant using the estimated defendant identifier. Any return to the court could be for a different offence type, for example, a defendant appearing in the court for a theft-related offence could later return for a drug-related offence. The analysis did not account for custodial periods which provide reduced opportunities to reoffend; this is caveated within the report.

Additionally, researchers linked Index of Multiple Deprivation (IMD) data to the Crown Court dataset to enable locality-based analysis. The most deprived 20% of small areas were identified and defendants in England and Wales were separated (as each country in the UK produces separate versions of IMD data with different indicators).

Research findings

The researchers found that, upon a defendant’s first known case in 2011, over half (56%) of defendants had returned to the magistrates’ courts by December 2019. This group included:

  • 17% who returned once
  • 18% who returned six or more times within this period.

The return rate to the magistrates’ courts varied by the defendant’s first offence. The highest rate of return was for defendants initially (in 2011) proceeded against for a theft offence; 82% of them returned to the magistrates’ courts by December 2019. The lowest rate of return across all offence groups was for sexual offences (43%). This could be due to longer custodial sentences imposed for sexual offences, reducing the opportunity to reappear again in front of the courts during the timeframe of this analysis.

Regardless of a defendant’s first offence group, many defendants later returned to the magistrates’ courts for some form of summary offence (a minor criminal offence). Defendants were most likely to return for the same offence group as their initial 2011 case, suggesting that the defendant could be specialising in their offence group.

The researchers found that the percentage of defendants who were sent to the Crown Court increased with the number of times they returned to the magistrates’ courts, following their initial case. This might indicate an escalation in returning defendants’ offending behaviour and subsequent sentences.

Linking the Crown Court data with the Index of Multiple Deprivation data enabled additional criminological theory driven analysis to be tested around the relationship between neighbourhood deprivation and criminality. In 2019, over 40% of defendants dealt with in the Crown Court resided in the most deprived 20% of neighbourhoods in England and Wales respectively (2011 Census population data).

The findings supported criminological theory and previous evidence on the relationship between neighbourhood deprivation and criminality; where offences are typically committed in close proximity to a defendant’s residence and that crime occurs in socially and economically disadvantaged neighbourhoods.

This over-representation of defendants dealt with in the Crown Court compared to the general population varied by offence groups. Defendants dealt with for a sexual offence in the Crown Court in 2019 were least likely to reside in the most deprived small areas in England (36%). By contrast, robbery (50%) and theft offences (50%) had the highest percentage of defendants who resided in the most deprived areas. Similar patterns were also found in Wales.

The findings are also aligned with established evidence on the links between neighbourhood deprivation and crime type-specific offending and offender characteristics. Area-based policy tools are likely to reduce crime and reoffending, for example, initiatives to improve residents’ health, education, employment and access to services.

Research impact

Since March 2022 when the research was published, the findings have been shared with ministers, analysts, and policy colleagues within the Ministry of Justice to inform understanding of repeat users of the justice system.

The early work has helped to build a fuller picture of defendants’ interactions with the criminal courts and how cases progress through the system. It enabled, for the first time, analysis to demonstrate the extent and nature of repeat court users at scale. These insights are critical to understanding what works to improve justice user outcomes.

The research demonstrates how linked administrative data can provide powerful new insights for policymaking and academic interrogation, especially in areas aligned to the Ministry of Justice’s the departmental priority to reduce reoffending.

The Ministry of Justice has been working in partnership with the ONS and ADR UK to encourage analysis of the newly linked data, for example through ADR UK Research Fellowships. Research includes exploring priority cross-cutting policy themes, such as ethnic disparities in the justice system. Fellows create Data Explained and Data Insights documents to help explain data issues and make their findings accessible to inform policy.

Research outputs

Publications and reports

Blogs, news posts, and videos

Presentations and awards

  • Linked Administrative Data, ONS Research Excellence Awards 2022
  • Ministry of Justice Data First academic seminars, October 2021 and November 2022
  • ADR UK Researcher Network Symposium on Crime and Justice, May 2022
  • British Society of Criminology Conference, June 2022
  • Royal Statistical Society Conference, September 2022
  • International Population Data Linkage Network Conference, September 2022
  • European Society of Criminology Conference, September 2022
  • DataConnect22 Conference, September 2022
  • Scottish Centre for Administrative Data Research (SCADR) Workshop Unlocking criminal justice data, October 2022
  • Ministry of Justice Data First Symposium, November 2022

About the ONS Secure Research Service

The ONS Secure Research Service is an accredited trusted research environment, using the Five Safes Framework to provide secure access to de-identified, unpublished data. If you use ONS Secure Research Service data and would like to discuss writing a future case study with us, please ensure you have reported your outputs here: Outputs Reporting Form




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