Causal chain analysis in systematic reviews of international development interventions

Abstract

Understanding the extent to which an intervention ‘works’ can provide compelling evidence to decision-makers, although without an accompanying explanation of how an intervention works, this evidence can be difficult to apply in other settings, ultimately impeding its usefulness in making judicious and evidence-informed decisions. In this paper, we describe causal chain analysis as involving the development of a logic model, which outlines graphically a hypothesis of how an intervention leads to a change in an outcome. This logic model is then used to anchor subsequent decisions in the systematic review process, including decisions on synthesis. In this paper, we outline the steps taken in building a logic model, which usually consists of a series of boxes depicting intervention components and processes, outputs, and outcomes with arrows depicting connecting relationships. The nature of these connecting relationships and their basis in causality are considered, through a focus on complex causal relationships and the way in which contextual factors about the intervention setting or population may moderate these. We also explore the way in which specific combinations of intervention components may lead to successful interventions. Evidence synthesis techniques are discussed in the context of causal chain analysis, and their usefulness in exploring different parts of the causal chain or different types of relationship. The approaches outlined in this paper aim to assist systematic reviewers in producing findings that are useful to decision-makers and practitioners, and in turn, help to confirm existing theories or develop entirely new ways of understanding how interventions to effect change.

PROTOCOL: What is the impact of complex WASH interventions on gender and social equality outcomes in low‐ and middle‐income countries? A mixed‐method systematic review protocol

“…Framework synthesis (Brunton et al, 2015, 2020; Macura et al, 2019) is a method for organising and synthesising diverse types of evidence as it can accommodate qualitative and mixed method studies. It can be used for studying complex interventions, while supplying (different types of) evidence across longer causal chains (Kneale et al, 2018). Framework synthesis is composed of six analytical stages including (1) familiarisation with the data; (2) framework creation or selection; (3) indexing of data according to a framework; (4) charting or rearranging the data according to the framework and potentially framework modification; (5) mapping and (6) interpretation.…”

Implementation of Home-Based Telerehabilitation of Patients With Stroke in the United States: Protocol for a Realist Review

“…This realist review aims to develop generalizable theories by examining each study to uncover the mechanism through which an implementation strategy works and the effects of various contexts on making it work [35]. The reviewers will untangle the complexity of implementation strategies through a frequent enhancement of the theoretical explanations of the empirical findings [36,37]. The output of this realist synthesis is a refinement of how the strategy "works, for whom, in what circumstances, in what respects and why?"…”

PROTOCOL: Involving men and boys in family planning: A systematic review of the effective components and characteristics of complex interventions in low‐ and middle‐income countries

“…The aim is to deepen our understanding of the dynamics of these interventions and allow us to provide recommendations for future research and the optimal use of evidence by decision makers, FP practitioners and intervention programmers. Using a Causal Chain Analysis (CCA) approach (Kneale et al, 2018), we will use the logic model presented in Figure 1 to frame both data extraction and subsequent CCA of intervention characteristics and outcomes.…”

“…We will adopt a CCA approach to analysis (Kneale et al, 2018). The logic model will inform pairwise analysis to identify which interventions are effective, mediator and moderator analysis to identify the pathways to effectiveness (quantitative CCA), and meta‐regression to assess the impact of specific components and characteristics and combinations of components and characteristics of effective interventions and/or moderation by characteristics of the population/setting.…”