Systems thinking is a problem-solving approach that considers the ‘whole system’ that might affect a public health problem, rather than just its individual parts. Academic and policy approaches to public health problems sometimes separate out issues into small parts, or deal with them in silos. For example, obesity (as a public health problem) is sometimes considered separately to the issue of mental health by academics and policy makers. The real world is often complex and interconnected. Systems thinking looks at the big picture and considers how the various elements of a system interact with each other. By considering the entire system, systems thinking allows for a more comprehensive understanding of problems and the potential consequences of different solutions. “Systems thinking encourages us to think (even more) about: How different individuals, populations, organisations and sectors relate to one another. How specific activities and changes in one part of a system may affect other parts – and vice versa – sometimes in unexpected ways. How to bring more synergy and coherence to our many different activities.” Egan et al. 2019 p7

A system map is a visual tool used to depict the components of a system (as we imagine it) and the relationships between them. System maps can: help us see the "big picture" and the complex web of connections within a system. show how elements are linked to help us understand how changes in one part of the system might affect other parts. be a great way to share a common understanding of a system among different stakeholders.

The map shows 139 factors that stakeholders involved in the development process identified as having influence on inequalities in health outcomes for children aged 0–25 years at the local level. We followed the example of the National Health Service (NHS) by including all children and young people aged 0-25 years. We defined ‘local’ as the geographical boundaries of the local authority, although we recognise that many components of the system are delivered by other organisations whose area of operation will not necessarily align with local authority boundaries. We chose to focus on the ‘whole system’ to ensure the map can support systems thinking in relation to a wide range child health outcome and a broad approach to addressing inequalities in child health. The map represents our expert participants’ understanding of the system that influences child health inequalities at the local level. It is not intended to be an accurate representation of an objective, observable system. The factors are organised in six domains. The service domain: Factors associated with the availability and delivery of public, private and third sector services that impact on child health outcomes. The economic domain: Factors that influence the economic resources, at household and local-area level, that are available to children and young people. The governance domain: Factors associated with development and implementation of policy to support child health and reduce inequalities at the local area level. The physical domain: Factors related to the physical environment (social spaces, physical infrastructure, local amenities) in which children and young people live. The social domain: Factors related to the people around children and young people who influence their health behaviours and outcomes, including parents and families, peer groups, local communities, and social media. The personal domain: Factors that refer to children and young people’s health-related behaviours and developmental outcomes that are known to be linked to health inequalities in later life.

We think that a visual depiction of the factors that affect child health can be useful to people working to improve child health outcomes. The map helps to show how interventions that focus on a single programme or policy are unlikely to have a significant impact on the complex issue of child health inequalities. We think that using the map to consider how the local system operates to produce inequalities can help to identify where interventions in the system can make best use of limited resources to reduce child health inequalities. Some of the ways the map could be used to support the work of professionals involved in developing strategies and interventions for improving child health outcomes include: bringing people together to support a shared understanding of ‘systems approaches’ clarifying who needs to be ‘round the table’ to address a child health challenge aiding discussion between different stakeholders working together on an initiative supporting intervention planners to specify which factors are/are not being targeted identifying potential unintended consequences of planned interventions identifying factors to evaluate within interventions supporting visualisation of local data & identify local data gaps Case study 1 summarises the ways in which the map has been used by one local authority to design services and activities to deliver a nutrition and healthy weight action plan. The map may also be useful as a teaching aid. Case study 2 provides an example of how the map has been used in teaching students at postgraduate level on public health courses in England.

We produced this systems map of child health in England to support public health professionals and others involved in child health who are working to reduce child health inequalities. Children in the UK have poor health compared to those in other Western European countries, and there are large and increasing health inequalities between children from the most and least deprived areas of the UK. In England, there are growing inequalities in child health outcomes, both within and between local areas. At the same time, there has been a reduction in resources available to health and social care services, with austerity measure having the greatest impact on children and young people in poorer areas. It is challenging to identify ways to reduce inequalities in child health due to the number of different policy areas that impact on child health outcomes, and because there are so many different organisations involved, each with its own priorities and ways of working. Applying a systems-based approach is one way to understand this complexity and to identify ways for organisations to work together to develop joined-up approaches to addressing child health inequalities.

In total, more than 125 stakeholders contributed to the development of the map through the following process: 1. We worked with two contrasting local authority sites. Two local authority areas were involved in the development of the child health systems map. One local authority was a city in the North of England, the other was a rural county in the Southwest of England. The sites differed in terms of the structure of local authority governance (one unitary authority, and one two-tier authority), the level of deprivation, and the proportion of black and minority ethnic residents. In each area we conducted qualitative interviews with senior decision makers with responsibility for child health and reviewed key local documents (e.g. Child Health and Wellbeing Strategy) to support researchers’ understanding of the local context. 2. We held group mapping workshops to produce local maps for each local authority site. In each site, professional stakeholders with responsibility for child were invited to take part in the mapping workshop. Participants included staff from the local authority, elected members, CCG, NHS and third sector organisations. Workshops were also held with children and young people (recruited through youth groups), and with parents/carers. In total, 6 workshops were held across the two sites. The format was similar for all workshops. although some adjustments were needed to make sure the children and young people’s workshop was delivered in an age-appropriate way. During workshops, participants were asked to consider two questions: a) What factors drive child health and wellbeing in [Site name]? b) What factors drive health inequalities between different groups of children and young people in [Site name]? Participants were first encouraged to generate as may factors (i.e. things that could be a determinant of child health outcomes) as they could think of. Secondly, working in small groups, the participants were invited to share and explain the factors they had identified. Finally, the groups clustered the factors and discussed the relationships between factors. 3. We used the knowledge we had collected from children and families, professionals, and academics to develop local child health system maps. Information from workshops in each site was used to develop area-specific systems map for each site, representing the different local child health systems. The maps showed the factors identified, and the links between factors described by workshop participants. Our workshops identified large numbers of factors to be included in the systems map and, to help us organise these in meaningful way, we used an existing framework, developed by Goldfeld et al (2015), that divides factors affecting child health and wellbeing into five ‘domains’. These domains (described below) provided a good fit with the information from our workshops, but we found that one additional domain was needed to capture factors identified by our participants that refer to children and young people’s health behaviours and outcomes. These site-specific maps were checked with professional stakeholders in each site and refined in response to feedback received. 4. We developed a ‘generic’ version of the map. The two local maps were merged to create a generic version of the child health system map that may be applied to any English local authority. This involved removing factors that were very area-specific, and adjusting factors that were similar but captured different levels of detail to achieve the ‘best fit’ to the combined information from across the two sites. 2. We asked national experts to help us refine the map. The final stage of developing the map involved two rounds of an online survey for national experts in child health, health inequalities and systems mapping. In the first round of the survey participants were asked to consider individual domains and whether any factors and the links between them were missing or incorrect. The map was refined in response to expert feedback and recirculated to the same participants to check their agreement to changes made. Further information about the development of the map can be found in: Jessiman P, Powell K, Williams P, Fairbrother H, Crowder M, Williams J & Kipping R (2021) A systems map of the determinants of child health inequalities in England at the local level. PLoS ONE, 16(2).

When we were developing the map, the personal characteristics and circumstances of some sub-populations of children and young people (e.g. gender, ethnicity, looked-after children) emerged as factors that increase the risk of poor health outcomes. However, we did not include this on the map as these inherent characteristics are not amenable to change by the local health system. When we consulted our expert workshop participants, they suggested that viewing the map through an ‘inequality lens’ for different groups may be useful for considering how the system results in different health experiences and outcomes for different groups of children and young people. As an example, the importance of factors associated with service accessibility will vary for children and young people of different genders and/or (dis)abilities. The subpopulations identified by our workshop participants as being at increased risk of poor health outcomes due to their personal characteristics and circumstances are: Age Asylum seeker/refugee status/citizenship status Ethnicity CYP who are members of Gypsy, Roma and Traveller communities Cultural and religious background CYP experiencing transition (of any type) Low birth weight CYP living with previously unsurvivable illness Gender identity CYP with physical disability Sexual identity CYP with intellectual disability CYP from military families CYP with autism spectrum disorder Young/teenage parents CYP with special educational needs and disability (SEND) Young carers CYP with experience of adverse childhood events (ACEs) Care leavers CYP with complex and/or long-term physical health conditions CYP in care (including those placed out of the local authority area) CYP with complex and/or long-term mental health conditions CYP at risk (e.g. on child at risk registers) CYP with genetic predisposition to disorder(s) Young offenders