Implications of a complexity perspective for systematic reviews and guideline development in health decision making

Abstract

There is growing interest in the potential for complex systems perspectives in evaluation. This reflects a move away from interest in linear chains of cause-and-effect, towards considering health as an outcome of interlinked elements within a connected whole. Although systems-based approaches have a long history, their concrete implications for health decisions are still being assessed. Similarly, the implications of systems perspectives for the conduct of systematic reviews require further consideration. Such reviews underpin decisions about the implementation of effective interventions, and are a crucial part of the development of guidelines. Although they are tried and tested as a means of synthesising evidence on the effectiveness of interventions, their applicability to the synthesis of evidence about complex interventions and complex systems requires further investigation. This paper, one of a series of papers commissioned by the WHO, sets out the concrete methodological implications of a complexity perspective for the conduct of systematic reviews. It focuses on how review questions can be framed within a complexity perspective, and on the implications for the evidence that is reviewed. It proposes criteria which can be used to determine whether or not a complexity perspective will add value to a review or an evidence-based guideline, and describes how to operationalise key aspects of complexity as concrete research questions. Finally, it shows how these questions map onto specific types of evidence, with a focus on the role of qualitative and quantitative evidence, and other types of information.

Prevention and control of cholera with household and community water, sanitation and hygiene (WASH) interventions: A scoping review of current international guidelines

“…Concordance scores may simply reflect a lack of detail or prioritisation of certain service areas, rather than explicit decisions to include specific interventions. Nevertheless, the less agreement, the more potential there is for inappropriate interventions or conflicted decision-making among national governments and responding organisations, and the more likely it is that evidence has not been considered systematically when developing guidelines [93,150], suggesting a need for greater scientific and policy collaboration among organisations.…”

“…None of the guidelines explicitly stated their process for guideline development such as using the GRADE system [151,152] or other recommended methods [93,150,153,154] to determine the quality of evidence for each recommendation. Any new development of guidelines should either use and adhere to these recommended processes to strengthen their quality and use, or clearly describe their methods.…”

Making nutrition guidelines fit for purpose

“…Taking a “complexity perspective” involves considering theory of change, causal pathways, complex systems properties, and context when conceptualising a review and when interpreting the evidence and formulating recommendations 25. Nutrition recommendations should be framed in a broader context than clinical recommendations, emphasising equity, human rights, and sociocultural acceptability as well as the benefits and harms of an intervention 26.…”

Health Inequality as a Large-Scale Outcome of Complex Social Systems: Lessons for Action on the Sustainable Development Goals

“…Developed during the 1980s, but new as coherent theories, complexity theory and its predecessor chaos theory, were the result of more than a century of scientific experimentation and theorising about how matter organises and behaves. Since the 1990s complexity theory began increasingly influencing thinking in a range of social sciences, including the health sciences where its use has become more widely accepted [5][6][7]. Complexity theory sees social phenomena, such as inequality, as the "emergent" result of interacting elements within a social system [52].…”

“…In Aotearoa New Zealand (NZ) the systemic pathways that lead to health inequality are becoming more widely understood [3]. Whilst failure to act effectively on large-scale health outcomes internationally has led to calls for a paradigm shift away from linear, siloed approaches to health and social intervention [4][5][6][7]. This paper explores two areas of knowledge-the evidence of health inequalities, and what we know about intervening in complex systems.…”