Child Outcomes for Mothers Facing Trial (COMFT): Protocol for a multi-national data linkage study to understand caregiver arrangements for children of mothers involved in the criminal and family justice systems

Abstract

Background
An unknown proportion of mothers are involved in both the Criminal Justice and Family Justice Systems. Mothers with cross-justice involvement are at risk of losing their children from their care on a temporary or permanent basis.

Objectives
Speaking directly to the Female Offender Strategy for England and Wales and the imperative to preserve mother-child relationships wherever safe and in the child's best interests, the Child Outcomes for Mothers Facing Trial (COMFT) study aims to uncover mothers' dual system involvement and provide vital insights about caregiver outcomes for children. The project will use administrative data to deliver the first-ever quantitative analyses of mothers and children at the intersection of the criminal and family justice systems.

Methods
The project will link female defendant records in England and Wales to mother and child family court records (public and private law), as well as demographic data. Data will be accessed through the globally leading Secure Anonymised Information Linkage (SAIL) Databank at Swansea University. The proposal has been developed collaboratively with project partners, committed to transforming justice outcomes for women and children, including the Ministry of Justice (MoJ), the Children and Family Court Advisory and Support Service (Cafcass), Cafcass Cymru and the leading charity, Birth Companions. Formal ethical approval has been granted by the Universities involved.

Patient and Public Involvement
A unique feature of this project is that from design to completion, a group of mothers with lived experience are directly involved. The 'COMFT-Together' advisory group ensures that the perspectives of women with cross-justice involvement inform this study, and that mothers benefit directly from a shared research role and curriculum facilitated by Birth Companions.

Implications
As the study is the first of its kind, it will also serve as an international exemplar, relevant to policy makers across the globe wishing to use routine organisational data to inform public services delivery.

Introduction

Policy Relevance and Overview

The preservation of family relationships is central to female offender strategies in England and Wales [1, 2]. Preserving mother-child relationships is associated with a reduction in female offending and provides vital continuities for children [3–5]. However, there continues to be considerable concern that progress towards family preservation is slow and there is insufficient baseline evidence against which progress can be measured [6, 7]. Critics continue to highlight the overuse of short-term prison sentences for women for non-violent offences, which have detrimental impacts on mother-child relationships far beyond the sentence [8, 9]. Approximately six in every ten women sentenced to custody are subject to short-term sentences (less than six months). The recent Independent Sentencing Review firmly acknowledged the potentially severe impact of even short-term custodial sentences, given women may lose their homes and care of their children. However, the Sentencing Bill stopped short of a presumption against short-term sentences and instead proposed suspended sentences [10].

Background: Community and Custodial Sentencing in England and Wales: Implications for Child Welfare and Protection

In Wales, rates of female imprisonment are the highest in the UK and there is an absence of women’s prisons in Wales, meaning mothers are detained in England at considerable distance from their children [9, 11]. In addition, for female defendants receiving community penalties there are different, but concerning questions about the demands that community sentences make on women at risk of family breakdown [12]. Although community sentences are associated with a lower rate of re-offending, questions about how the demands of community sentences interact with the demands of child protection involvement are insufficiently examined. The lack of data about female defendants subject to non-custodial sentences and their children has been raised as a major concern by leading advocacy organisations, who argue that this undermines effective policy making and evaluation [13]. The most recent statistics from the MoJ indicate that in 2023, around 236,900 females were formally dealt with by the criminal justice system (CJS), either by an out of court disposal or court proceedings [14]. According to statistics compiled by Cafcass (England) in the fiscal year 2024/25, the organisation received 16,195 children’s public law cases, and 39,182 private law cases. This is a combined total of 55,377 cases, the majority of which will involve a mother [15]. In Wales, case numbers are smaller, and data is unavailable in terms of a differentiation of either mothers or children’s family court cases. In 2023, and based on data from 2015/16, the MoJ estimated the cost of female offending to the Government at £1.7B, excluding (unknown) costs for intergenerational offending [2]. However, in the absence of quantitative cross-justice insights, it is impossible to ascertain the scale or pattern of women’s multiple system involvement, or caregiver outcomes for children.

Rationale: Impact of CJS and FJS Involvement and Gaps in the Evidence Base

The difficulties experienced by many women involved in the CJS and Family Justice System (FJS) overlap. Difficulties include mental distress and disability, substance misuse, domestic abuse, poverty and homelessness [9, 12, 16–18]. Women’s CJS involvement impacts child wellbeing and outcomes [19, 20]. Yet, cross-justice planning, and co-ordinated policy solutions are hampered by a lack of joined-up research about interactions between these two sectors of justice in the lives of children and families [7, 12]. Innovative practice solutions which offer an intensive, joined-up approach to families, remain thin on the ground, despite positive evaluative evidence of services such as Changing Futures [21] which start with a holistic view of the individual in need.

Vital questions also remain unanswered about the link between system involvement and child outcomes for minoritised populations, particularly given racial disparities in both the CJS and FJS [13, 22–24]. The history of family justice is of limited generation and application of population-scale empirical evidence [25, 26] and there is a dearth of robust cross-justice empirical evidence at scale. In this context, the work of pioneering family justice research teams [27–31, e.g.], the leadership of Administrative Data Research (ADR) UK, the Data First team within the Ministry of Justice and the campaigning by the Nuffield Family Justice Observatory are all welcome developments in ensuring that answers to pressing policy questions and practice transformation are firmly grounded in empirical evidence. The Data First project [32], a major UK government data linkage programme led by the Ministry of Justice represents a significant step forward in this area as the project aims to unlock the potential of administrative justice data for research by linking datasets across justice and wider public services and making them available to accredited researchers. The CJS and FJS have the potential to deliver effective and equitable solutions to support women’s rehabilitation and prevent family breakdown – or to make matters worse.

Concerns about the impact of women’s CJS involvement on their relationships with their children have led to a body of high quality and valuable qualitative research which has consistently reported adverse effects on mother-child relationships [17, 19, 20, 33–36, e.g.]. However, this has not been matched by a body of robust cross-justice quantitative research [37]. Knowledge, derived from population-scale datasets, about the involvement of female offenders in both public and private family law cases is wanting. The dearth of quantitative research leaves many vital policy questions unanswered [7]. Indeed, even the most basic questions about how many female defendants have dependent children are insufficiently answered based on current research or national statistics [38–40], although from recent statistics, it is estimated that between October 2021 and October 2022 there were 192,912 children with a parent in prison [41]. Moreover, the qualitative evidence is weighted towards the prison population rather than the broader population of female offenders. By providing quantitative evidence, we provide answers to questions that are long overdue and complement valuable in-depth qualitative research.

Purpose of the Current Study

The overarching aim of the Child Outcomes for Mothers Facing Trial (COMFT) study (2025–2027) is to generate new methodological and substantive knowledge, which will enable the justice system (CJS and FJS) to have a better understanding of how its actions serve to preserve or disrupt relationships between mothers and children, and to inform joined-up policy and practice solutions. This aim will be achieved by linking female defendant and mother and child family court records (England and Wales) and conducting further linkages for Wales to include records for Children Looked After (CLA). The learning from the lengthy permissions processes will be separately reported, including how issues of risk of re-identification were resolved among data owners, such as MoJ. Regarding risk of de-identification, this is a particular concern when multiple datasets are linked together. Although all data will be de-identified, individuals may unintentionally become identifiable when information is assembled from different data sources. To mitigate this risk, the research team adhere to principles of data minimisation (i.e., a proportionate approach to variable requests and particular attention to sensitive information); aggregation of variables also provides researchers with a further method of privacy protection. Alongside the substantive value of COMFT, this study is an important test case in respect of the letter of, but also the interpretation of the Digital Economy Act 2017 [42], which provides the lawful basis for the access, sharing and linking of de-identified administrative data for research in the public interest. The value and limitations of the data will be carefully documented to facilitate use by a broader community of researchers, and two experimental sub studies will be completed delivering new substantive knowledge. Regarding terminology, throughout this article, we refer to ‘sex’ rather than ‘gender’, because the binary classification better reflects how individuals are generally reported or managed through the CJS.

Context: Justice Systems and Legislative Frameworks

This study takes place within the legal and administrative framework of England and Wales, whose justice and child welfare systems shape both the generation of administrative data and the processes for accessing and linking those data for research.

The criminal justice system in England and Wales is structured in tiers. Less serious offences are typically handled in Magistrates’ Courts, while more serious offences are heard in the Crown Court. The Crown Court deals with indictable criminal cases, serious sentencing decisions, and appeals from Magistrates’ Courts. Proceedings in the Crown Court may involve a judge and, in trial cases, a jury. Because the Crown Court handles more serious offences and produces detailed case level records, its data are frequently used in justice-related administrative research.

Child welfare and family law matters are overseen by the Family Justice System. This system includes local authorities responsible for safeguarding and promoting children’s welfare, as well as family courts that make legal decisions where concerns about a child’s safety or wellbeing arise. Family justice proceedings may include applications for care orders, supervision orders, or other protective measures, and are initiated when authorities believe statutory intervention is required to protect a child. These proceedings generate administrative and court records relating to children, parents, and case outcomes, which may be linked with other government datasets for approved research purposes.

Together, the criminal courts and the FJS operate within a broader statutory and data governance framework that regulates how administrative data are collected, shared, and accessed for research under defined legal, ethical, and security safeguards. These institutional structures influence both the availability of the data used in this study and the procedures required for secure linkage and analysis. Data access and linkage are governed in part by the Digital Economy Act 2017 [42], which enables approved research use of administrative data under defined safeguards.

Partnerships and Beneficiaries

The project has been developed collaboratively by an established group of researchers (Lancaster and Swansea Universities and the University of Lancashire) with project partners: the MoJ, the Children and Family Court Advisory and Support Service (Cafcass), Cafcass Cymru, Birth Companions and an advisory group of mothers with lived experience (COMFT-Together). Partners share a common goal to transform outcomes for female offenders and their children. Priority research questions were confirmed through a series of stakeholder events including a national multi-stakeholder conference with 350 attendees and subsequent stakeholder meetings. Beneficiaries include policy makers charged with the delivery of female offender policies in England and Wales; practitioners who make best interest decisions for children in the family courts or offer family preservation services, families involved with the CJS and FJS — as well as academics and government departments (national and international) wishing to pursue cross-justice research using administrative data. Throughout this programme of research, the challenge afforded by the (birth) mothers steering group is invaluable (COMFT-Together), both in respect of the acceptability of the research project and use of de-identified personal data, analytic questions posed of the linked data, but also the interpretation of findings and shaping of recommendations.

Research Questions

Regarding female defendants appearing in datasets made available by the Data First project, namely the magistrates’, Crown Court and prisoner custodial journey datasets for England and Wales, the project will address the following 7 research questions.

1. What is the value of linked female defendant and family court data for research, and what are the limitations of these data?
2. Do female defendants in the magistrates’, Crown Court and prisoner journeys data also appear in the FJS (public and private law) and what can be learned about the demographic profile of these women and patterns of cross-justice involvement?
3. Who are the children in the FJS (public and private law) of female defendants, and what kind of legal proceedings concern these children?
4. What are the legal order outcomes for children in public and private law cases, when mothers are defendants in the magistrates’ and Crown Court?
5. Are mothers’ patterns of offending, FJS involvement, and demographic profiles associated with particular FJS outcomes for their children?
6. For female defendants in Wales, what is the total number and demographic profile of mothers and their dependent children, and what proportion of these children have been looked after or been subject to FJS proceedings?
7. For all dependent children of female defendant mothers in Wales, what are the caregiver arrangements for children and what is the geographical distance between children and their mothers, when children are no longer in their care?

Research questions 6 & 7 apply to Wales only, as the Secure Anonymised Information Linkage (SAIL) Databank (described below) holds data on the full population of women in Wales, their dependent children as well as the national CLA data; these data are not currently available for England. As with any novel linkage study which tests the boundaries of data owners understanding and approach to risk management, the team may revise the listed research questions, also in dialogue COMFT-Together.

Methods

Study Design

This is a multi-national retrospective data linkage study using routinely collected data held in the SAIL Databank (www.saildatabank.com). The SAIL Databank is a privacy-protecting data safe-haven containing anonymised, individual-level data about the population of Wales, and more recently England, including health, social care, justice, and demographic data [43, 45, 46]. A sequential study design is proposed, which begins with exploration of data quality and scope, dataset build and data documentation (Research Question 1). This is followed by two experimental sub studies (Research Questions 2–5 and 6–7) which will provide completely new knowledge about mothers and children at the intersection of the criminal and family justice systems. Each element of the study builds incrementally towards new knowledge about the profile of women and children, and children’s caregiver arrangements (e.g. placed with extended family, foster carers or for adoption). Depending on data quality and completeness, demographics will include the age of the women and children at different points of the study (e.g. age at first contact with the CJS/FJS, age at first birth), ethnicity, deprivation, and rurality. For each research question outlined earlier, we will conduct appropriate comparisons using the four key subsamples derived from the data linkage process:

1. Mothers involved in both the FJS and CJS
2. Mothers involved in the FJS only
3. Mothers involved in the CJS only
4. The general population (non-CJS/non-FJS involved)

Data Sources

Data sources include Data First’s magistrates’, Crown Court and prisoner custodial journey datasets [32]; records produced routinely by Cafcass (England) and Cafcass Cymru [47, 48] census records for England and Wales; the CLA Wales dataset [49]; the Welsh Demographic Service Dataset (WDSD); the Welsh National Community Child Health Database (NCCHD); the Maternity Indicators Dataset (MIDS); and the Welsh Birth and Death registers. For each dataset within the SAIL Databank, data are anonymised via a standard split-file and linkage process, described elsewhere [43, 45]. Unique identifiers, called Anonymised Linking Fields (ALF for Wales and ALF2 for England) enable linkage of their records across datasets. The full list of data sources that will be used in the study are described in Table 1.

Table 1: List of Data Sources that will be Linked in the Child Outcomes for Mothers Facing Trial (COMFT) Study.

Dataset name	Dataset description	Key information	Data owner
Data First Magistrates’ Courts defendant case level dataset (MACO)	Individuals appearing as defendants in criminal cases dealt with by the magistrates’ court in England and Wales	Defendant characteristics, offence information, court proceedings and outcomes	MoJ
Data First Crown Court defendant case level dataset (CRCO)	Individuals appearing as defendants in criminal cases dealt with by the Crown Court in England and Wales	Defendant characteristics, offence information, court proceedings and outcomes	MoJ
Criminal Court Journey (MAGS_CROWN_JOURNEY)	Links the Magistrates’ Courts defendant dataset (MACO) to the Crown Court defendant dataset (CRCO)	Linking fields	MoJ
Data First prisoner custodial journey dataset (PRIS)	Individuals serving custodial sentences in England and Wales who appear within records from the prison data source	Offence information, sentence length and release information	MoJ
Cross-Justice Link (CROSS_DATASET_LINK)	Links Magistrates’ Courts, Crown Court and First Prisoner datasets	Linking fields	MoJ
Data First family court (FACO)	Individuals involved in family court cases in England and Wales	Demographics, case and event-level information including case type, hearings and outcomes	MoJ
Cafcass England (CAFE)	Individuals involved in family court proceedings in England	Demographics, relationships, case level information including case type and legal outcomes	Cafcass
Cafcass Cymru (CAFW)	Individuals involved in family court proceedings in Wales	Demographics, relationships, case level information including case type and legal outcomes	Cafcass Cymru
Census 2021 (CENS)	ONS population census for England and Wales, capturing demographic, housing, employment, education, and health information	Demographics, including ethnicity and deprivation, and relationship information	ONS
Census 2011 Wales (CENW)	ONS population census for Wales, capturing demographic, housing, employment, education, and health information	Demographics, including ethnicity and deprivation, and relationship information	ONS
Looked After Children Wales (LACW)	Local authority information about looked after children submitted annually to Welsh Government	Episode level information including dates, placements and legal status	Welsh Government
Welsh Demographic Service Dataset (WDSD)	Register of all individuals registered with a Welsh General Practice (GP) and individual’s anonymised address	Demographics, residential information	Digital Health and Care Wales
Annual District Birth Extract (ADBE)	Register of all births in Wales	Demographics, birth information	ONS
Annual District Death Extract (ADDE)	Register of all deaths relating to Welsh residents	Demographics, death information	ONS
National Community Child Health Database (NCCHD)	Child Health System in Wales; includes birth registration and monitoring of child health examinations and immunisations	Demographics, maternal information, birth information	Digital Health and Care Wales
Maternity Indicators Dataset (MIDS)	Data relating to women at initial assessment and to mother and baby for all births in Wales	Demographics, mother information, birth information	Digital Health and Care Wales

Ethics and Data Governance

This study has required scrutiny and multiple approvals from several research approval panels. The first of its kind, it inevitably raises completely new questions in respect of privacy protection and risk of re-identification. Formal ethical approval was obtained from Lancaster University (approval number 5210). The SAIL Information Governance Review Panel (IGRP) granted approval to access and link the data within SAIL (project number 1605). The IGRP is an independent panel of representatives from relevant organisations who review all applications for use of data held in the SAIL Databank, ensuring that the proposed research complies with information governance principles and represents an appropriate use of data in the public interest [43]. Data will be linked and analysed within the SAIL Databank secure research environment and treated in accordance with the Data Protection Act 2018 [50] and the principles underlying the General Data Protection Regulation [51]. Cafcass, Cafcass Cymru and Welsh Government consented to the use of family court and children looked after data. The project was also subject to detailed scrutiny by His Majesty’s Courts and Tribunal Service (HMCTS) and His Majesty’s Prison and Probation Service (HMPPS) approval panels, to enable access to crime data. The Office for National Statistics (ONS) approved use of Census 2021 data, and finally, the UK Statistics Authority confirmed that the project is consistent with the scope and objectives of the Digital Economy Act. All data owners and the SAIL Databank consult regularly on the public acceptability of the use of administrative data for research purposes. In addition, and regarding the specific focus of the project, the project team also tested the acceptability of the project with the dedicated Birth Mothers Advisory Group who are COMFT-Together.

Data Exploration, Dataset Build and Documentation

Given there has been no work previously to link mother and child administrative records across the CJS and FJS, by necessity, the first stage of the project will comprise considerable work of cleaning, harmonising, restructuring, and sequencing data, alongside documenting data quality and scope. Dataset construction will follow a staged linkage strategy:

1. Family Court Dataset (FCD)We will extract and harmonise data from Cafcass England (CAFE) and Cafcass Cymru (CAFW), identifying valid public and private law cases where at least one child subject and one female respondent (mother) are present. Internal relationship tables will be used to establish mother-child links. These cases and individuals will then be linked to the MoJ Family Court Dataset (FACO) using case and person identifiers (Case-Court-Ref-hash, ALF/ALF2), enriching the dataset with additional attributes (see Figure 1).
2. Criminal Court Dataset (CCD)Female defendants will be identified from magistrates’ (MACO) and Crown Court (CRCO) records, linked using MAGS_CROWN_JOURNEY, and supplemented with custodial journeys from PRIS. Integration will be achieved through MoJ’s CROSS_DATASET_LINK, producing a unified criminal court dataset (see Figure 2).
3. Dual System Dataset (DSD)The FCD and CCD will be linked at the person level using ALF/ALF2 and CROSS_DATASET_LINK to identify women present in both family and criminal justice datasets. This dual system dataset forms the core analytical resource for the study (see Figure 3).
4. Welsh Dataset (WD)For Wales, the DSD will be further linked to health, child welfare and demographic datasets (e.g. WDSD, LACW, NCCHD, MIDS, ADDE, ADBE, Census 2011 Wales), offering wider contextual insights into justice-involved families (see Figure 4).
5. Final Research Dataset (FRD)The DSD will also be linked to Census 2021 (England and Wales), yielding a highly enriched, longitudinal dataset suitable for multidisciplinary analysis (see Figure 5).

Figure 1: Family Court Dataset (FCD).

Figure 2: Criminal Court Dataset (CCD).

Figure 3: Dual System Dataset (DSD).

Figure 4: Welsh Dataset (WD).

Figure 5: Final Research Dataset (FRD).

The data coverage provides a minimum observational window of 10 years. Regarding the size of the populations of mothers and children involved, precise figures can only be ascertained through the work conducted in the initial stages of the project. However, as above, in 2023, around 236,900 females were formally dealt with by the CJS [14]. Over a minimum 10-year observational window, this figure will multiply — although a high proportion of female defendants are repeat defendants. The work carried out in the initial stages will ascertain the total population of unique mothers in the CJS, across our observational window. Using public and private law children’s case data, in the absence of any national mother-level data, we estimate that there will be between 55,000 and 65,000 mother-records in England alone, per year, with a further small number of cases in Wales (less than 3,000). This figure will multiply over a 10-year observational window, but again, a proportion of mothers will be recurrent. The number of children linked to unique mothers will be higher, as women typically have more than one child. The team have extensive experience of identifying unique mothers in the FJS, avoiding double-counting because of mother’s repeat appearances [30] and constructing mother-child relationships [27, 28].

Analysis

To deliver new knowledge, analyses will comprise the production of descriptive statistics, alongside statistical modelling. Analytic work will follow careful curation of the datasets, evaluation of data quality and the production of documentation. Given the absence of basic epidemiological data about mothers and children at the intersection of the CJS and FJS, descriptive statistics will be produced comprising volumes, proportions, and demographic profiles of mothers and children. Maternal and child characteristics will be profiled, given the over-representation of women in the CJS from deprived areas and minority ethnic groups. Further, descriptive analytic work will aim to ascertain maternal pathways between the CJS and FJS to examine the women’s combined appearances and exposure to the FJS and CJS (during a 10-year observational window), and children’s exposure to the FJS. The findings from the descriptive analyses will lay the groundwork to enable a more nuanced understanding of the factors influencing children’s caregiver arrangements at the intersection of the CJS and FJS. A preliminary analysis plan has been developed in accordance with the proposed research questions and will be revised as necessary. To examine the associations between mothers’ offending and FJS histories, and outcomes such as mother-child separation, we will employ Latent Growth Mixture Modelling (LGMM) [52] and Event History Analysis (EHA) [53] techniques.

Further Analysis for Wales

The unique environment of the SAIL Databank and the availability of further demographic and children’s social care data will enable the team to conduct a further experimental study for Wales and build a more comprehensive picture of outcomes regarding children’s relationships with their mothers and alternative caregivers. Building on learning from the first stages, we will build a more complex linked dataset for Wales. Specifically, we will use the National Community Child Health Database (NCCHD) and Maternity Indicators Dataset (MIDS), containing birth registration data for all children born in Wales, including a maternal ALF, to link women with their biological children. This will enable us to capture all children linked to female defendants in Wales, to understand their demographic profiles. We will also use the Welsh Demographic Service Dataset (WDSD), the Annual District Birth Extract (ADBE) and the Annual District Death Extract (ADDE) containing administrative information and sociodemographic characteristics for the resident population of Wales registered with a Welsh GP (including children). Further, we will link to the CLA data. These steps will help us to identify children in Wales who have and have not been involved with the family courts and/or care system, to estimate the proportion who have been looked after or who have been subject to FJS proceedings. We will also use the CLA data to establish more precisely placement/permanency arrangements (kin, foster care, adoption, return home) for children, who are looked after in public care. Social care (CLA) data provides actual placement information and is therefore a better indicator of caregiver arrangements for public law children than the proxy measure (legal order data) within Cafcass or Cafcass Cymru. In addition, we will use SAIL’s Residential Anonymous Linkage Field (RALFs) to ascertain small-area measures of deprivation (Welsh Index of Multiple Deprivation 2019 [54] and explore spatial patterns within this population. Utilising the RALF system will enable us to understand where children live and with whom, and the geographic distance from their birth mothers. Thus, this analysis for Wales, will enable a broader view of mothers in the CJS and their children in Wales, which will provide the justice system (CJS and FJS) with a better understanding of how their actions serve to preserve or disrupt relationships between mothers and children.

Inclusion of Mothers with Cross-Justice Lived Experience

A unique feature of this study is that it has been designed with mothers with lived experience(s) who will form an advisory group: “COMFT-Together”. The COMFT-Together advisory group ensures that the study is shaped and challenged by the voices of women with cross-justice lived experiences, who are typically marginal to research and policy development. To ensure safe and meaningful participation for the mothers, they will be supported by our highly experienced practice partner, Birth Companions (BC). BC will establish a participation curriculum for mothers and will also provide responsive support to mothers, ensuring principles of voluntarism and reciprocal benefit underpin women’s engagement. Translation of findings for lay audiences (family and community audiences) and podcast material produced by Birth Companions and the mothers reference group “COMFT-Together”, will ensure our outputs are inclusive and reach families themselves.

Involvement of Practitioners, Policy Makers and Advocates

“COMFT- Challenge” will comprise an advisory board of cross-justice academics, policy makers, practitioners and family advocates positioned to challenge the team and ensure ready pathways to impact. Online meetings will be scheduled 2-3 times per year, with terms and conditions requiring additional ad hoc advice. COMFT-Challenge will ensure that the recommendations from the project are shaped by those with frontline expertise, increasing the likelihood of uptake and influence.

Dissemination and Impact

Exchange workshops (the “COMFT-Dialogue” series) will be hosted by the team, to share interim insights about the value of the data and linkage opportunities. We will publish final data documentation, code and descriptive profiles of the study populations and data resource profiles. Because the study will adopt best practice in the reproducibility of research Reproducible Analytical Pipelines (RAP) approach [55], future researchers will be able to undertake research which builds on this foundational project. Full and accessible summary reports will be produced, alongside peer-reviewed academic publications, infographics and maps. An end of project conference will be hosted; the team will disseminate via national and international conferences. Findings will be of direct relevance to the implementation of the Female Offender Strategy [1, 2], and to practice initiatives which aim to preserve mother-child relationships. Careful attention has been paid to maximising pathways to impact in the selection of project partners and broader engagement strategy. Our standpoint is that the design and interpretation of research is more than a technical exercise [25], rather it requires collaborative expertise to translate messages for the real world. A project website and social media strategy, agreed with project partners, will establish the project’s identity and support wider communications. A dual and multi-format publication strategy will ensure that outputs meet the needs of a range of audiences. Given the topicality of this project in cognate justice systems, we envisage considerable interest in the US, Canada and Australia. The team have considerable international links. An end of project conference funded by Lancaster Data Science Institute will target national and international audiences.

Conclusions

This is a completely novel complex data linkage project which will generate important substantive knowledge of direct relevance to the current Female Offender Strategy for England and Wales, as well as vital questions of caregiver arrangements for children when mothers have cross-justice involvement. In addition, the project will deliver vital insights about data quality, scope and cross-justice linkage opportunities. By embedding knowledge exchange throughout the project, the project will generate learning which reaches a wider community of academic and analyst colleagues. By centring the voices of mothers with lived experience, the project ensures that questions and recommendations resonate those directly involved with justice systems. Overarching is the pursuit of innovative policy and practice solutions which preserve rather than disrupt mother-child relationships, in a context of limited justice innovation in this respect [56].

Funding

This work is supported by the Economic and Research Council (Responsive Grants, Rounds I. Grant Ref ES/Z503575/1)

Acknowledgements

We acknowledge partnerships with the Ministry of Justice Data First Team, Amy Summerfield and Stephen Jobling, Birth Companions, our advisory group of mothers with lived experience, Cafcass, Cafcass Cymru and Welsh Government.

Statement of conflicts of interest

None.

Ethics Statement

See the “Ethics and data governance” section within the main manuscript.

Data Availability Statement

The SAIL Databank (https://saildatabank.com/) will be used to access all data for this study. The data is accessible via a two-stage application process consisting of scoping and governance review to assess user and project approvals.

AI disclosure Statement

The authors declare that no generative AI tools were used in the preparation of this manuscript.

Authors’ Contributions

KB and LJG conceptualised the study. KB, LEC, LJG, BA and LN drafted the first iteration of the manuscript. All authors critically reviewed the manuscript, provided important intellectual input, approved the final version and agreed to be accountable for their contributions.

References

1. Ministry of Justice (MoJ). Female offender strategy. June 2018. https://assets.publishing.service.gov.uk/media/5b3349c4e5274a55d7a54abe/female-offender-strategy.pdf.

2. Ministry of Justice (MoJ). Female offender strategy delivery plan 2022–2025. January 2023. https://assets.publishing.service.gov.uk/media/63d78f63e90e0773e01f8960/female-offender-strategy-delivery-plan-2022-25.pdf.

3. Corston J. The Corston report: A review of women with particular vulnerabilities in the Criminal Justice System. London: Home Office; 2007. https://prisonreformtrust.org.uk/wp-content/uploads/2022/08/The-Corston-Report.pdf.

4. Corston J. Women in the Penal System: Second report on women with particular vulnerabilities in the Criminal Justice System. London: Howard League for Penal Reform; 2011. https://howardleague.org/wp-content/uploads/2016/04/Women-in-the-penal-system.pdf.

5. Lord Farmer. The importance of strengthening prisoners’ family ties to prevent reoffending and reduce intergenerational crime. London: Ministry of Justice; August 2017. https://assets.publishing.service.gov.uk/media/5a81d6b2e5274a2e87dbfc00/farmer-review-report.pdf.

6. Women in Prison. The Corston Report 10 years on. How far have we come on the road to reform for women affected by the criminal justice system? 2017. https://www.cleanbreak.org.uk/media/uploads/corston-report-10-years-on.pdf.

7. National Audit Office. Improving outcomes for women in the criminal justice system. Ministry of Justice. London: National Audit Office; 2022. https://www.nao.org.uk/wp-content/uploads/2022/01/Improving-outcomes-for-women-in-the-criminal-justice-system.pdf.

8. Pitman J & Hull J. Counting the cost of maternal imprisonment. London: Crest Advisory; 2021. https://64e09bbc-abdd-42c6-90a8-58992ce46e59.usrfiles.com/ugd/64e09b_284d145bef104d0f8ad2ff371e48bf78.pdf.

9. Prison Reform Trust. Why focus on reducing women’s imprisonment? England and Wales. August 2022. https://prisonreformtrust.org.uk/wp-content/uploads/2022/08/Why-women-2022-briefing.pdf.

10. Women in Prison. We’ve graded the UK Government’s Sentencing Bill efforts to transform the justice system for women. September 2025. https://womeninprison.org.uk/news/weve-graded-the-uk-governments-sentencing-bill-efforts-to-transform-the-justice-system-for-women.

11. Fraser D. There are no women’s prisons in Wales. What does this mean for Welsh women? Clean Break; 2018. https://www.cleanbreak.org.uk/hub/there-are-no-womens-prisons-in-wales-what-does-thi/.

12. Birth Companions. A window of opportunity. Understanding the needs and experiences of pregnant women and new mothers in contact with the criminal justice system in the community in England. London: Clinks; May 2021. https://cdn.prod.website-files.com/68ba883839431f9b4ab9a8f8/68c2bd7bfed04c1af0ecac43_Birth%20Companions_Clinks_Window%20of%20opportunity.pdf.

13. Working Chance. A lost focus on community solutions. Our response to the Prisons Strategy White Paper. 2021. https://workingchance.ams3.cdn.digitaloceanspaces.com/media/documents/Blog-_Prisons_White_Paper_response.pdf.

14. Ministry of Justice. Statistics on Women and the Criminal Justice System 2023. January 2025. https://www.gov.uk/government/statistics/women-and-the-criminal-justice-system-2023/statistics-on-women-and-the-criminal-justice-system-2023-html.

15. Cafcass 2025. Annual data summaries. https://www.cafcass.gov.uk/about-us/our-data/annual-data-summaries.

16. Broadhurst K & Mason C. Child removal as the gateway to further adversity: Birth mother accounts of the immediate and enduring collateral consequences of child removal. Qualitative Social Work. 2020; 19(1): 15–37. 10.1177/14733250198934

    10.1177/14733250198934

17. Baldwin L. Tainted love: the impact of prison on maternal identity, explored by post prison reflections. Prison Service Journal. 2017; 233: 28–34. https://www.nicco.org.uk/userfiles/downloads/5ac5cb09f0422-tainted-love-lucy-baldwin.pdf.

18. Gelsthorpe L. After Corston: community, change and challenges. In L Moore, P Scraton and A Wahidin (Eds). Women’s Imprisonment and the Case for Abolition. Critical Reflections on Corston Ten Years On. Abingdon, Oxon: Routledge. 2018.

19. Minson S. Direct harms and social consequences: An analysis of the impact of maternal imprisonment on dependent children in England and Wales. Criminology and Criminal Justice. 2019; 19(5): 519–536. 10.1177/1748895818794790

    10.1177/1748895818794790

20. Minson S. Maternal Sentencing and the Rights of the Child. Cham, Switzerland: Palgrave Macmillan. 2020. 10.1007/978-3-030-32738-5

    10.1007/978-3-030-32738-5

21. Ministry of Housing, Communities and Local Government. Evaluation of the Changing Futures programme. Fourth interim report. February 2025. https://assets.publishing.service.gov.uk/media/67a47f27baccec3af36b3bfc/Evaluation_of_the_Changing_Futures_programme_-_fourth_interim_report.pdf.

22. Uhrig N. Black, Asian and Minority Ethnic disproportionality in the Criminal justice system in England and Wales. London: Ministry of Justice. 2016. https://assets.publishing.service.gov.uk/media/5a75928440f0b6360e475224/bame-disproportionality-in-the-cjs.pdf.

23. Cox J & Sack-Jones K. “Double disadvantage”: The experiences of Black, Asian and minority ethnic women in the criminal justice system. Women in Prison and Agenda. April 2017. https://womeninprison.org.uk/media/downloads/double-disadvantage-1.pdf.

24. Alrouh B, Hargreaves C, Cusworth L, Broadhurst K, North L, Griffiths, L et al. What do we know about ethnic diversity in the family justice system in England? London: Nuffield Family Justice Observatory. 2022. https://www.nuffieldfjo.org.uk/wp-content/uploads/2022/05/nfo_summary_diversity_england_20220526_FINAL.pdf.

25. Broadhurst K, Cusworth L, Harwin J, Alrouh B, Bedston S, Trinder L et al. Scaling up research on family justice using large-scale administrative data: an invitation to the socio-legal community. Journal of Social Welfare and Family Law. 2021; 43 (3): 237–255. 10.1080/09649069.2021.1953856

    10.1080/09649069.2021.1953856

26. Robertson L, & Broadhurst K. Introducing social science evidence in family court decision-making and adjudication: Evidence from England and Wales. International Journal of Law, Policy and the Family. 2019; 33:(2),181–203. 10.1093/lawfam/ebz002

    10.1093/lawfam/ebz002

27. Broadhurst K, Alrouh B, Yeend E, Harwin J, Shaw M, Pilling M. Connecting events in time to identify a hidden population: birth mothers and their children in recurrent care proceedings in England. British Journal of Social Work. 2015; 45(8): 2241–2260. 10.1093/bjsw/bcv130

    10.1093/bjsw/bcv130

28. Griffiths LJ, Johnson RD, Broadhurst K, Bedston S, Cusworth L, Alrouh B, Ford DV & John A. Maternal health, pregnancy and birth outcomes for women involved in care proceedings in Wales: a linked data study. BMC Pregnancy Childbirth. 2020; 20, 697. 10.1186/s12884-020-03370-4

    10.1186/s12884-020-03370-4

29. Johnson RD, North L, Alrouh B, John A, Jones K, Akbari A, Smart J, Thompson S, Hargreaves C, Doebler S, Cusworth L, Broadhurst K, Ford DV, Griffiths LJ. A population level study into health vulnerabilities of mothers and fathers involved in public law care proceedings in Wales, UK between 2011 and 2019. International Journal of Population Data Science. 2022;7(1):1723. 10.23889/ijpds.v6i1.1723

    10.23889/ijpds.v6i1.1723

30. Alrouh B, Abouelenin M, Broadhurst K, Cowley L, Doebler S, Farr I et al. Mothers in recurrent care proceedings. New evidence for England and Wales. London: Nuffield Family Justice Observatory. 2023. https://www.nuffieldfjo.org.uk/wp-content/uploads/2022/11/nfjo_eng_report_newborn_recurrence_20221111_final-1.pdf.

31. Ireland G, Wiljaars L, Jay MA, Grant C, Pearson R, Downs J, Gilbert R. Social and health characteristics of mothers involved in family court care proceedings in England. 2024. https://www.nuffieldfoundation.org/wp-content/uploads/2019/11/Nuffield_Social_Health_Mothers-in-care-proceedings_final20240829.pdf.

32. Ministry of Justice (MoJ). Data First: An Introductory User Guide. Harnessing the potential of linked administrative data for the justice system. May 2025. https://assets.publishing.service.gov.uk/media/683863d5c99c4f37ab4e867c/Data_First_User_Guide_Version_8.2.pdf.

33. Baldwin, L. Mothering Justice: Working with Mothers in Criminal and Social Justice Settings. Hampshire: Waterside Press. 2015.

34. Prison Reform Trust. Women’s Voices – London. January 2020. https://prisonreformtrust.org.uk/wp-content/uploads/2022/01/Womens-Voices-LONDON-FINAL.pdf.

35. Abbott L, Scott T & Thomas H. Compulsory separation of women prisoners from their babies following childbirth: Uncertainty, loss and disenfranchised grief. Sociology of Health and Illness. 2023; 45(5): 971–988. 10.1111/1467-9566.13423

    10.1111/1467-9566.13423

36. Grace S. Hearing the Voices of Women involved in Drugs and Crime. In Grace S, O’Neill M, Walker T, King H, Baldwin L, Jobe A, Lynch O, Measham F, O’Brien K & Seman V (Eds). Criminal Women: Gender Matters. Bristol, Bristol University Press. 2022:14–36. 10.46692/9781529208443.003

    10.46692/9781529208443.003

37. Broadhurst K, Griffiths L, Abouelenin M, Alrouh B & Cowley L. Female defendants and their children: Who’s counting? A review of the quantitative evidence. Working Paper, Centre for Child and Family Justice Research, Lancaster University. (Available from lead author). 2023.

38. Galloway S, Haynes A. & Cuthbert C. An unfair sentence: spotlight on the Criminal Justice System. London: NSPCC; 2014. https://hubble-live-assets.s3.eu-west-1.amazonaws.com/birth-companions/file_asset/file/47/An_Unfair_Sentence_Spotlight_On_The_Criminal_Justice_System.pdf.

39. Joint Committee on Human Rights. The right to family life: children whose mothers are in prison. September 2019. https://publications.parliament.uk/pa/jt201719/jtselect/jtrights/1610/report-files/161002.htm.

40. Kincaid S, Roberts M. & Kane E. Children of prisoners: Fixing a broken system. London: Crest. February 2019. https://64e09bbc-abdd-42c6-90a8-58992ce46e59.usrfiles.com/ugd/64e09b_eab0853990d54c999ce1d03de1f30557.pdf.

41. Ministry of Justice (MoJ). Official statistics in development: Estimates of children with a parent in prison. July 2024. https://www.gov.uk/government/statistics/estimates-of-children-with-a-parent-in-prison/official-statistics-in-development-estimates-of-children-with-a-parent-in-prison.

42. Digital Economy Act 2017 c.30. Available at: https://www.legislation.gov.uk/ukpga/2017/30/contents.

43. Ford DV, Jones KH, Verplancke JP, Lyons RA, John G, Brown G, Brooks CJ, Thompson S, Bodger O, Couch T, Leake K. The SAIL Databank: building a national architecture for e-health research and evaluation. BMC Health Services Researc. 2009;9:157. 10.1186/1472-6963-9-157

    10.1186/1472-6963-9-157

44. Lyons RA, Jones KH, John G, Brooks CJ, Verplancke JP, Ford DV, Brown G, Leake K. The SAIL databank: linking multiple health and social care datasets. BMC Medical Informatics & Decision Making. 2009; 9: 3. 10.1186/1472-6947-9-3

    10.1186/1472-6947-9-3

45. Jones KH, Ford DV, Thompson S, Lyons RA. A Profile of the SAIL Databank on the UK Secure Research Platform. International Journal of Population Data Science. 2019;4(2):1134. 10.23889/ijpds.v4i2.1134

    10.23889/ijpds.v4i2.1134

46. Jones KH, Ford DV, Jones C, Dsilva R, Thompson S, Brooks CJ, Heaven ML, Thayer DS, McNerney CL, Lyons RA. A case study of the Secure Anonymous Information Linkage (SAIL) Gateway: a privacy-protecting remote access system for health-related research and evaluation. Journal of Biomedical Informatics. 2014;50(100):196-204. 10.1016/j.jbi.2014.01.003

    10.1016/j.jbi.2014.01.003

47. Bedston SJ, Pearson RJ, Jay MA, Broadhurst K, Gilbert R, Wijlaars L. Data Resource: Children and Family Court Advisory and Support Service (Cafcass) public family law administrative records in England. International Journal of Population Data Science. 2020;5(1):1159. 10.23889/ijpds.v5i1.1159

    10.23889/ijpds.v5i1.1159

48. Johnson RD, Ford DV, Broadhurst K, Cusworth L, Jones K, Akbari A, Bedston S, Alrouh B, Doebler S, Lee A, Smart J, Thompson S, Trinder L & Griffiths LJ. Data Resource: population level family justice administrative data with opportunities for data linkage. International Journal of Population Data Science. 2020; 5(1). 10.23889/ijpds.v5i1.1339

    10.23889/ijpds.v5i1.1339

49. Allnatt G, Lee A, Scourfield J, Elliott M, Broadhurst K, & Griffiths L. Data resource profile: children looked after administrative records in Wales. International Journal of Population Data Science. 2022;7(1):1752. 10.23889/ijpds.v7i1.1752

    10.23889/ijpds.v7i1.1752

50. Data Protection Act 2018, c. 12. Available at: https://www.legislation.gov.uk/ukpga/2018/12.

51. Council regulation (EU) 2016/679 of the European Parliament and of the Council of 27 April 2016 on the protection of natural persons with regard to the processing of personal data and on the free movement of such data (United Kingdom General Data Protection Regulation). Available at: https://www.legislation.gov.uk/eur/2016/679.

52. van der Nest G, Lima Passos V, Candel MJJM, van Breukelen GJP. An overview of mixture modelling for latent evolutions in longitudinal data: Modelling approaches, fit statistics and software. Adv Life Course Res. 2020;43:100323. 10.1016/j.alcr.2019.100323

    10.1016/j.alcr.2019.100323

53. Broström, G. (2022). Event History Analysis with R (2nd ed.). Chapman and Hall/CRC. 10.1201/9780429503764

    10.1201/9780429503764

54. Welsh Government. Welsh Index of Multiple Deprivation (full Index update with ranks): 2019. https://www.gov.wales/welsh-index-multiple-deprivation-full-index-update-ranks-2019.

55. Government Analysis Function Team. Reproducible Analytics Pipeline Strategy. 2022. https://analysisfunction.civilservice.gov.uk/policystore/reproducible-analytical-pipelines-strategy/.

56. Harwin J, Broadhurst K, Cooper C, & Taplin S. Tensions and contradictions in family court innovation with high-risk parents: The place of family drug treatment courts in contemporary family justice. International Journal of Drug Policy. 2019; 68, 101–108. 10.1016/j.drugpo.2018.04.019

    10.1016/j.drugpo.2018.04.019