Ministry of Justice: Data First
Source: gov.uk (2025-11-06)

Data First is a pioneering data-linking, research and academic engagement programme led by the Ministry of Justice and funded by ADR UK.

Data First unlocks the potential of the wealth of data created by the Ministry of Justice (MOJ) by making linked administrative datasets from across the justice system available for research. The programme is led by MOJ and funded by Administrative Data Research UK (ADR UK) (https://www.adruk.org/our-work/browse-all-projects/data-first-harnessing-the-potential-of-linked-administrative-data-for-the-justice-system-169/), an investment by the Economic and Social Research Council (ESRC).

Data from the courts, prison and probation services in England and Wales have been linked to enable new and innovative analysis of user journeys, interactions, and outcomes across the justice system. The programme is also enhancing the linking of justice data with other government departments, including education data from the Department for Education’s (DfE) National Pupil Database (NPD).

Data First enables researchers across government and academia to access these datasets in an ethical and responsible way via secure platforms in the ONS Secure Research Service (https://www.ons.gov.uk/aboutus/whatwedo/statistics/requestingstatistics/secureresearchservice) and SAIL Databank (https://saildatabank.com/).

By working in partnership with academic experts to facilitate and promote research in line with evidence priorities set out in the MOJ Areas of Research Interest (ARI) (https://www.gov.uk/government/publications/ministry-of-justice-areas-of-research-interest-2020) Data First is generating new insights to inform the development of government policy and drive real progress in improving justice outcomes.

General programme information

The Data First user guide provides further information about the programme, including the processes for accessing the data for research. The privacy and data protection statement provides information about how we use and share data.
- Data First user guide (https://assets.publishing.service.gov.uk/media/683863d5c99c4f37ab4e867c/Data_First_User_Guide_Version_8.2.pdf) (PDF, 768 KB, 34 pages)
- Data First privacy and data protection statement (https://assets.publishing.service.gov.uk/media/6099053bd3bf7f2887b642bd/data-first-privacy-statement.pdf) (PDF, 199 KB, 12 pages)
- MoJ-DfE data share privacy and data protection statement (https://assets.publishing.service.gov.uk/media/68f2032028f6872f1663efb8/MoJ_DfE_data_privacy_notice__002_.pdf) (PDF, 221 KB, 9 pages)
Data First datasets

Data First cross-justice system datasets

Data First has shared seven datasets derived from administrative sources across the justice system in England and Wales. These include data from magistrates’ courts, the Crown Court, prisoner custodial journeys, probation services, offender assessments, and both the family and civil courts.

To support analysis, a cross-justice system linking dataset is available. This dataset enables person-level linkage across the seven datasets and also includes a case-level linking table for connecting the magistrates’ courts and Crown Court data.

Data First Ministry of Justice-Department for Education (MoJ-DfE) data share

Separately, criminal history data from the Police National Computer (PNC) has been linked to education and social care data in England, sourced from the DfE’s National Pupil Database (NPD) as part of the MoJ-DfE data share. For the most up-to-date metadata relating to this data share, please contact either xxx@xxx.xx (mailto:xxx@xxx.xx) or xxx@xxx.xx (mailto:xxx@xxx.xx).

Data catalogues

Data catalogues are available for all Data First cross-justice system datasets, providing information on the variables contained within each.
- Data First magistrates' courts defendant data catalogue (https://assets.publishing.service.gov.uk/media/667e83b5aec8650b10090146/ONS_mags_gov_uk_v2.ods) (ODS, 464 KB)
- Data First Crown Court defendant data catalogue (https://assets.publishing.service.gov.uk/media/6647711ef34f9b5a56adca2e/ONS_CR_1.ODS) (ODS, 213 KB)
- Data First prisoner custodial journey data catalogue (https://assets.publishing.service.gov.uk/media/66e1b246caa02d92e72c8dae/ONS_prison_gov_uk_v2.ods) (ODS, 249 KB)
- Data First family court data catalogue (https://assets.publishing.service.gov.uk/media/669e739dab418ab055592a7a/ONS_family_gov_uk_v1.ods) (ODS, 81.8 KB)
- Data First probation data catalogue (https://assets.publishing.service.gov.uk/media/664771634f29e1d07fadca71/ONS_PR_1.ODS) (ODS, 112 KB)
- Data First cross-justice system linking data catalogue (https://assets.publishing.service.gov.uk/media/669e77f50808eaf43b50d46b/ONS_linking_gov_uk_v1.ods) (ODS, 23.2 KB)
- Data First civil court data catalogue (https://assets.publishing.service.gov.uk/media/688b45382c36111a67d5b7ea/ONS_civil_gov_uk_v1.ods) (ODS, 112 KB)
- Data First offender assessment data catalogue (coming soon)
Synthetic datasets

Data First has released eight low-fidelity synthetic datasets, these can be accessed via the UK Data Service (https://datacatalogue.ukdataservice.ac.uk/searchresults?search=synthetic+data+first&sort=2&tab=0) (UKDS). These datasets replicate the structure of the Data First cross-justice system datasets, without containing any real information about the individuals or cases in our secure datasets. They have been designed to help researchers become familiar with the data structure, prepare feasible research proposals, and develop analytical plans and code for deployment once research projects and secure access are approved.

To access the synthetic datasets, researchers must register for a UKDS account (https://ukdataservice.ac.uk/help/registration/registration-login-faqs/) and agree with the terms and conditions stated in the UKDS End User Licence Agreement (https://ukdataservice.ac.uk/app/uploads/cd137-enduserlicence.pdf).

Available synthetic datasets include:

Ministry of Justice Synthetic Data First Family Court, England and Wales, 2011-2023 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9399#details)

Ministry of Justice Synthetic Data First Offender Assessment Dataset, England and Wales, 2011-2023 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9401#details)

Ministry of Justice Synthetic Data First Prison Iteration 2, England and Wales, 2011-2023 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9400#details)

Ministry of Justice Synthetic Data First Probation Iteration 2, England and Wales, 2014-2023 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9398#details)

Ministry of Justice Synthetic Data First Civil Court Iteration 2, England and Wales, 2011-2022 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9397#details)

Ministry of Justice Synthetic Data First Magistrates Court Iteration 2, England and Wales, 2011-2023 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9396#details)

Ministry of Justice Synthetic Data First Crown Court Iteration 2, England and Wales, 2013-2023 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9395#details)

Ministry of Justice Synthetic Data First Cross-Justice System Linking Dataset, England and Wales, 2011-2023 (https://datacatalogue.ukdataservice.ac.uk/studies/study/9394#details)

Limitations of data linking

Users should note that the accuracy of data linking is determined by the availability of personal identifying information in source data. All available identifiers have been used during the matching process, but the availability of demographic information varies by dataset. The Data First criminal justice datasets (magistrates’ courts, Crown Court, prisoner custodial journey, probation and offender assessments) contain numerous, well-populated identifiers. The family and civil court datasets however are less well-populated. This impacts on how linkage occurs and will need to be considered as part of designing research projects. Further details can be found within the user guide and relevant data catalogues, and researchers are welcome to contact us to discuss project ideas at their earliest convenience so we can advise on viability.

Applying for data access

Data First datasets can be accessed through the ONS Secure Research Service (SRS) or SAIL Databank (except for the MOJ-DfE data share, which is only available through the ONS SRS).

Requests to access data through the ONS SRS require completion of the Secure Access to Data Form (https://assets.publishing.service.gov.uk/media/65c25c77a6838e001349d585/application-form-secure-access-data_01022024.docx), which can be accessed here (https://www.gov.uk/government/publications/moj-data-first-application-form-for-secure-access-to-data) along with additional supporting documents.
- For access to Data First datasets (covering courts, prisoner custodial journey, probation and offender assessments datasets), the application form should be submitted to xxx@xxx.xx (mailto:xxx@xxx.xx)
- Applications for the MOJ-DfE dataset should be directed to xxx@xxx.xx (mailto:xxx@xxx.xx) and xxx@xxx.xx (mailto:xxx@xxx.xx).
- For all MOJ justice datasets (except the MOJ-DfE dataset) applicants will also need to complete the Research Project Application form (https://www.ons.gov.uk/aboutus/whatwedo/statistics/requestingstatistics/secureresearchservice/applyforanaccreditedresearchproject), which will be assessed by the UK Statistics Authority Research Accreditation Panel (RAP).
Guidance for completing the application form can be found in the Data Sharing Guidance (https://assets.publishing.service.gov.uk/media/62038afa8fa8f510b357cc44/data-sharing-guidance-researchers.pdf), and the list of datasets and access routes can be found here (https://assets.publishing.service.gov.uk/media/62038b53e90e077f6ffa5dc9/available-data-modes-access.ods). Further information on the process overall is included within the Data First user guide above.

To access data within the SAIL Databank please apply though SAIL (https://saildatabank.com/data/apply-to-work-with-the-data/).

A register of external research projects which have been approved to use MOJ data is available to view here (https://assets.publishing.service.gov.uk/media/648184bb5f7bb7000c7fa6ae/approved-external-data-requests-log_-_May_2023.ods).

Analytical outputs

Statistical and social research publications using Data First data have been delivered by MOJ analysts or in collaboration with other government departments. Outputs have also been produced by ADR UK-funded Research Fellows. These publications can be found below:
- Data First Research Bulletin July 2024 (https://assets.publishing.service.gov.uk/media/66a8e11dfc8e12ac3edb0735/Data_First_Research_Bulletin_MoJ.pdf) (PDF, 206 KB, 15 pages)
- Data First Research Bulletin November 2025 (https://assets.publishing.service.gov.uk/media/690c901768fffdd77951aaf2/Research_bulletin_November_2025.pdf) (PDF, 364 KB, 23 pages)
- Data First: Criminal Courts Linked Data (https://www.gov.uk/government/publications/data-first-criminal-courts-linked-data)
- A Profile of Repeat Offending by Children and Young People in England and Wales (https://www.gov.uk/government/publications/a-profile-of-repeat-offending-by-children-and-young-people-in-england-and-wales)
- Education, children’s social care and offending (https://www.gov.uk/government/publications/education-childrens-social-care-and-offending)
- Criminal courts research fellows (https://www.adruk.org/our-work/browse-all-projects/adr-uk-research-fellows-the-first-users-of-the-data-first-magistrates-and-crown-court-datasets-422/)
- Family court – Cafcass research fellows (https://www.adruk.org/our-work/browse-all-projects/adr-uk-research-fellows-understanding-experiences-of-the-family-justice-system-826/)
- Probation and criminal justice system research fellows (https://www.adruk.org/our-work/browse-all-projects/adr-uk-research-fellows-the-first-users-of-the-data-first-probation-and-criminal-justice-linked-datasets-new63fdc70162868654419743/#:~:text=ADR%20UK%20is%20funding%20two,of%20the%20criminal%20justice%20system.)
- MOJ-DfE research fellows (https://www.adruk.org/our-work/browse-all-projects/adr-uk-research-fellows-ministry-of-justice-and-the-department-for-education-linked-datasets-fellowships-509/)
- ADR UK PhD studentships (https://www.adruk.org/our-work/browse-all-projects/adr-uk-phd-studentships-cohort/)
- Cross-justice system research fellows (https://www.adruk.org/our-work/browse-all-projects/adr-uk-research-fellows-2024-data-first-cross-justice-system/)
- MoJ-DfE research fellows 2nd cohort (https://www.adruk.org/our-work/browse-all-projects/adr-uk-research-fellows-ministry-of-justice-department-for-education-linked-dataset/)
- MoJ Evaluation Accelerator Fund Research fellow analysis: Assessing the effectiveness of Radio Frequency Electronic Monitoring (https://www.gov.uk/government/publications/assessing-the-effectiveness-of-radio-frequency-electronic-monitoring)
Splink: Data linkage at scale

Through Data First, MOJ has developed a free and open-source software library to enable data linkage at scale. This software has been used to link some of the largest datasets held by MOJ as part of Data First.

Splink is a freely available, open-source Python package that is:
- faster and more accurate than other free tools
- able to link large datasets, of tens of millions of records or more
- developed with advice from academic experts in data linkage
- able to produce a wide range of interactive data visualisations that help to build effective models, explain linkage predictions, diagnose problems and quality assure models
- compatible with multiple databases and big data processing engines, meaning it can run on a wider range of computer systems
You can find out more on the Splink website (https://moj-analytical-services.github.io/splink/), where you can download and start using Splink. You can also ask us a question (https://github.com/moj-analytical-services/splink/discussions) or raise an issue (https://github.com/moj-analytical-services/splink/issues) on the public GitHub repository (https://github.com/moj-analytical-services/splink). Splink are happy to hear from researchers interested in using the software for their work.

Awards and Recognition
- Innovation in Methods, Analysis in Government Awards 2020, Splink: Probabilistic Data Linkage at Scale (https://www.gov.uk/government/news/launch-of-the-analysis-in-government-awards)
- Innovative Methods, Analysis in Government Awards 2022, the Data Linking team (runner-up) (https://analysisfunction.civilservice.gov.uk/news/announcing-all-winning-entries-in-the-analysis-in-government-awards-2022/)
- Linked Administrative Data Award, ONS Research Excellence Awards 2022, ‘Data First: Criminal Courts Linked Data’ (https://www.ons.gov.uk/aboutus/whatwedo/statistics/requestingstatistics/onsresearchexcellenceaward)
- Collaboration Award, Analysis in Government Awards 2024, Data First Team (https://analysisfunction.civilservice.gov.uk/news/announcing-all-winning-entries-in-the-fourth-analysis-in-government-awards/)
Contact

Contact the Data First team at xxx@xxx.xx (mailto:xxx@xxx.xx) if you would like further information or have any queries.