Work Package One: Systems Science Work Package Investigators: Mark Petticrew, Cécile Knai, Sharon Friel, Niamh Fitzgerald, Nathan Critchlow, Anna Gilmore, Jeff Collin, Jamie Pearce, Katherine Severi, Nason Maani Hessari Aim: To develop methods to apply a complex systems perspective to public health problems, in the context of Unhealthy Commodity Producers (UCPs). Objectives: Develop a methodological approach that can be applied to a range of UCPs and different types of research over the lifespan of SPECTRUM, including new primary studies and evidence syntheses; Apply this approach in new case studies, chosen to allow the analysis of the system-level drivers of specific public health harms related to unhealthy commodities, thereby identifying leverage points in the relevant systems. Methods and Data Sources: This WP will address such issues directly by working with key PH stakeholders (including policymakers and the public) to develop and apply a systems approach – with the aim of understanding the problem better, and identifying potential solutions. Alcohol marketing is a good topic to start with because it offers the possibility of comparing a systems-based and a non-systems based approach. Systems perspectives take account of the interaction between local activities and interventions, and the wider system (such as the food system, or alcohol system), and are increasingly widely advocated within public health; policymakers, researchers and practitioners. Despite this, public health improvement often takes quite an atomistic approach, focusing on interventions which are isolated from the wider context or system. This means that such interventions (whether individually-delivered interventions, or public policies) may not work because their effects are moderated/ suppressed by aspects of that system which lie outside the intervention; and because the interventions themselves do not aim to change aspects of the system which most strongly influence public health, and health inequalities. Our first project sets out to explore how to take a systems thinking approach in systematic reviews. We will first conduct a critical analysis of a recent Cochrane on restricting alcohol advertising via the application of guidance published by Petticrew, Knai et al in 2019 on operationalising a systems approach in systematic reviews. The Cochrane review by Siegfried et al (2014) is selected as a case study for this exercise as it is an example of a systematic review which has employed such a narrow definition of the admissible evidence that the number of studies included was very limited, and the findings are ultimately not useful. We will take the new-published framework for conducting evaluations and systematic reviews from a systems perspective, as well as drawing on additional work published by the team, and adapting and applying this to a new critical analysis, focussed on alcohol marketing. The key data sources will be previous academic evaluations and reviews, as well as industry data on the processes and mechanisms by which advertising works, and the outcomes of advertising campaigns. We will also compare the findings to previous systematic reviews that have not adopted a systems approach, and will set out how the approach can be applied to other CDOH topics (e.g. systematic reviews focussed on other unhealthy commodities). In particular we will assess the potential for transferring this new conceptual model and our general methodological approach to other unhealthy commodities or services (such as HFSS foods), to specific policy mechanisms such as public-private partnerships, and to particular settings and/or populations (e.g. schools, and children and young people) within the whole system. Subsequent WP1 projects are currently being developed and will include a study to create system maps with young people and other key stakeholders on the drivers of alcohol harms, with a focus on marketing, and on what systems-level interventions may be effective; and qualitative research presenting interviewees with vignettes on different topics using misinformation – and asking them about their interpretation, followed by system mapping the participants to explore the drivers of misinformation around food, alcohol and other unhealthy commodities, and entry points in the system for addressing these.