Various terms have developed to describe systems approaches, systems perspectives, systems thinking, and complex or whole systems approaches. These approaches point to the need for a greater engagement with the complex landscape or system in which public health interventions are embedded.
Dr McGill cited Donella Meadows’ definition of a system as “a set of things – people, cells, molecules or whatever – interconnected in such a way that they produce their own pattern of behaviour over time” (Meadows, 2008: 2).
Systems are not static. They are constantly changing, for example, as providers and initiatives are added and withdrawn, as strategic priorities and budgets change, and as social and cultural attitudes shift. Any new initiative will be affected by this evolving wider system and will likewise impact on it.
Find out more about what systems thinking is in NIHR SPHR Guidance on Systems Approaches to Local Public Health Evaluation. Part 1: Introducing systems thinking, co-authored by Prof. Egan, Dr McGill and other members of the NIHR School for Public Health Research (SPHR) in 2019.
In conventional public health evaluations, the intervention activity is isolated to measure change in the pre-determined outcomes. Contamination and confounding factors need to be minimised because they could obscure assessment of the intervention’s effectiveness. Systems thinkers argue that whilst this leads to a tidier evaluation, it is artificial because in the real world, interventions rarely operate in a vacuum. We might also want to evaluate policy and practice changes which are not discrete interventions with fixed start and end points.
Systems approaches recognise that plans to introduce something new into a particular context need to anticipate interactions with existing actors, activities and relationships. An intervention’s impact will depend on multiple contextual factors beyond that intervention itself. Equally, because complexity is a property of the system rather than, necessarily, the intervention itself, even a simple intervention can lead to complex consequences. Through identifying and analysing these factors and consequences, systems approaches can target changes needed at a system level and improve the transferability of public health interventions.
By its nature, systems thinking looks at the big picture-macro level and attempts to explain interaction within and across systems. For intervention evaluation, it can be useful to complement systems approaches with logic-model or theory of change development to understand change at the micro and meso levels of ‘everyday’ public health interventions, and how they connect to wider systems.
Systems approaches are increasingly being advocated for, with the NIHR Public Health Research programme encouraging applicants to adopt a systems perspective where appropriate. Dr McGill expands on the benefits of systems approaches in this video, drawing on her own evaluation of an alcohol levy on licensed premises.
Systems approaches can use various methods, including:
Concept mapping – mapping which factors/drivers are key to understanding and improving health and social care. For example, what factors contribute to population mental health and wellbeing?
Network analysis – mapping who the key stakeholders/agents are and analysing relationships between them to understand, for example, the links that organisations have with one another or gaps in provision.
Systems modelling – statistical modelling of different hypothetical scenarios. This can help to predict impacts and unintended consequences over time. For example, what impact could e-cigarettes have on the smoking of tobacco products and associated health impacts?
More guidance on methods for systems evaluation can be found in NIHR SPHR Guidance on Systems Approaches to Local Public Health Evaluation. Part 2: What to consider when planning a systems evaluation, produced by Prof. Egan, Dr McGill and NIHR SPHR colleagues.
If you're interested in exploring further how to use a systems approach in your health and/or social care services research application, do please contact your local RDS for our free and confidential methodological advice and support.