Navigating the Swampy Lowlands: Developing Methods for ‘Big Picture’ Evidence Synthesis

This thesis aims to demonstrate, with a critical analysis of my publications, my original and substantial contribution to the development of evidence synthesis methodology addressing broad research questions. I use Big Picture reviews as an umbrella term to describe scoping, mapping and evidence gap map methodologies, which I have applied to broad questions in different topic areas. I also aim to demonstrate my original contribution to the topic areas in which I have applied Big Picture methods, a critical reflection of the methods and areas for future methodological research. Methods Seven included papers (Papers A-G) are used to illustrate how I have interrogated the existing ‘big picture’ review methods, applied them to address a variety of Big Picture review questions, and identified numerous contradictions and inconsistencies within the methods literature and offered solutions to enable others to navigate them. I demonstrate how critical reflection led me to identify limitations when applying recommended methods but also led me to develop novel methods to overcome these limitations. I draw upon Barnett’s work (1997, 2015) on ‘criticality’ as a framework within each chapter to demonstrate how critical thinking and critical reflection has led to critical action. The aim of higher education should be to create learning environments that nurture a critical being; meaning the learner moves beyond thinking and reflection towards action. It therefore is consistent with the aims of this thesis, to show those stages in my own learning and progress as an academic. Findings This thesis describes how, while leading, seven reviews using Big Picture methods I have applied critical thinking, reflection and action which has led to my own academic development, and enabled me to make a unique contribution to both Big Picture methods as well as to the topic areas I explored. The body of work that I describe in this thesis has underpinned a shared understanding amongst methodological leaders in this field of how the methodological approaches of scoping and, mapping reviews and Evidence and Gap Maps have evolved, and how different terminology describing very similar approaches has arisen. I focused leaders thinking towards a synoptic vision to achieve a consistent approach to review type classification and appropriate use of methodological guidance and reporting standards (Paper A). As well as describing how my reflections have resulted in action, this thesis also affords the opportunity to reflect further on my development as a methodologist and demonstrate how I have applied my own expertise in the reviews. In undertaking a series of reviews using Big Picture review methods I interrogate the methodological guidance underpinning their use, and develop a skill set that has enabled me to apply the methods across a variety of topic areas. These include, the methods of qualitative evidence synthesis (Paper B), preterm birth (Paper C), mass screening programmes (Paper E) and intergenerational interventions (Paper F) I present this series chronologically through the different stages of the review process, contrasting the methods used in ‘big picture’ reviews with standard systematic reviews of effectiveness and the challenges that these present. I reflect on approaches to stakeholder engagement, and how this affects effective dissemination of outputs. I also identify challenges encountered and consider how our methods might evolve in order to improve approaches in future reviews (Paper F). I describe the particular challenges for locating evidence when the question is broad and the search yield might be unmanageably high for review teams to screen. This work led to further methodological developments, with the creation of a filter to identify studies undertaken in LMIC contexts (Paper D). Increasingly, the output from these approaches that commissioners value is the interactive visual map. I also reflect on how growing methodological expertise has enabled me to cross fertilize knowledge, apply techniques learned in one topic area, and apply them in another. I describe an innovation, introducing evidence and gap map methodology to tumour classification, taking it from the social and environmental sciences and applying it in pathology (Paper G). This work has precipitated the development of a new hierarchy of evidence within pathology. A large component of my work has been in training and supporting review groups to undertake these types of reviews and to work closely with knowledge users to ensure our review outputs are meeting a need and filling a gap. Impact Statement Identifying the inconsistencies and lack of clarity in the terminology used for these types of review methods has precipitated an acknowledgement that such a lack exists (Paper A). I have demonstrated why this lack of clarity has arisen and proposed a route to future clarification. This has led to accepted presentations at key conferences (Cochrane Colloquium 2023, What Works Global Summit 2022, 2023) and ongoing methodological research to help to shape future reporting guidance. Introducing this method to colleagues working at the WHO IARC (World Health Organisation, International Agency for Research on Cancer) led to a successful grant to map evidence to support tumour classification that informs practice globally. Acting as a methodological expert has provided me with the opportunity of moving methods across topic areas and in so doing has advanced the uptake of evidence in fields where progress has been slow. Evidence synthesis is a dynamic field of scientific innovation, where methods are evolving and technology is rapidly advancing. This thesis also reveals ongoing questions I am seeking to answer, and a programme of work that is current and live. I intend to continue to contribute positively to the methods of Big Picture evidence synthesis.