Systems thinking is a conceptual approach that can assist stakeholders in understanding complexity and making progress on persistent public health challenges. Neglected tropical diseases (NTDs), a complex global health problem, are responsible for a large disease burden among impoverished populations around the world. This aim of this study was to better discern the many complexities of the global NTD system in order to identify and act on leverage points to catalyse progress towards ending NTDs.
Existing frameworks for systems change were adapted to form the conceptual framework for the study. Using a semi-structured interview guide, key informant interviews were conducted with NTD stakeholders at the global level and at the country level in Nigeria. The interview data were coded and analysed to create causal loop diagrams that resulted in a qualitative model of the global NTD system.
The complete qualitative model is discussed and presented visually as six separate sub-components that highlight key forces and feedback loops within the global NTD system.
We identified five leverage points for NTD system change, namely (1) clarify the potential for and assess realistic progress towards NTD elimination, (2) increase support for interventions besides drug delivery, (3) reduce dependency on international donors, (4) create a less insular culture within the global NTD community, and (5) systemically address the issue of health worker incentives. The specific findings for NTDs raise a number of uncomfortable questions that have not been addressed, at least in part, because it is easier to continue focusing on ‘quick win’ solutions. The study provides a model of a systems thinking approach that can be applied to other complex global health and development challenges in order to understand complexity and identify leverage points for system change.
Neglected tropical diseases (NTDs) are an example of a global health issue for which sustainable progress will depend on stakeholders’ ability to think systemically about potential solutions. Along with many of the world’s most persistent public health challenges, NTDs can be considered as ‘complex’, ‘wicked’ or ‘adaptive’ problems [1, 2]. These types of problems and their root causes are often difficult to define and their solutions are typically unclear [3]. Rather than relying on blueprint approaches or technical solutions, making headway on complex problems requires a whole systems perspective that incorporates adaptation and group learning [4,5,6,7]. Systems thinking is a conceptual approach that seeks a better understanding of complexity in order to increase the ability of stakeholders to influence durable change to address complex problems [8,9,10,11].
At its core, a system is a collection of parts that, through their interactions, form a whole with properties beyond the sum of the component parts [12, 13]. Natural and human systems have high levels of dynamic complexity that arises from the interaction of multiple agents over time [14]. Many health sector problems are considered complex due to the interconnectedness of highly heterogenous groups of actors operating with multiple interrelated and simultaneous strategies in a constantly changing context [7, 15, 16]. Gaining a holistic perspective of complex problems embedded in complex systems is critical to identifying solutions with the potential for lasting change [4, 6, 10]. Systems thinking is a discipline for expanding our understanding of complex situations by seeing wholes, patterns and interrelationships rather than separate system parts [6]. Thinking in this way allows us to identify root causes of problems and see new opportunities for progress [17]. In approaching problems and solutions through this lens, systems thinking helps us to overcome the linear and reductionist approaches commonly applied to problem solving in the social sectors and to reinvent our policies and institutions according to this holistic, dynamic view [5].
In practice, systems thinking includes a broad array of qualitative and quantitative methods and tools designed to better understand system behaviours and intervene in the context of complexity and uncertainty [18]. Many systems thinking tools are designed to assist stakeholders in co-producing knowledge about a system and in visually capturing and communicating this information [19,20,21]. On the qualitative side, soft systems methodology uses the idea of complexity as an interrogative tool for stimulating debate and learning, building relationships, and galvanising people into action [19, 22, 23]. The focus with this approach is on engaging multiple stakeholders in developing ‘rich pictures’ of a problem situation that help to make explicit the mental models held by those with differing perspectives [5, 7, 20, 22]. On the quantitative side, system dynamics modelling is a methodologically demanding tool that incorporates data into simulations of system behaviour in order to describe a system and its operations [14, 20]. These models allow testing of hypotheses in the context of complexity in order to help identify the few key areas in which policy-makers should focus their attention [5, 24]. System dynamic modelling also allows users to see how the system may evolve and how changes may affect it over time [25]. System dynamics models built through group processes are useful in harnessing the perspectives and insights of stakeholders with the most experience interacting with the systems addressed in the models [24].
Causal loop diagrams are essential components of quantitative system dynamic models, but they can also be used to build stand-alone qualitative system models that visually map feedback loops depicting the interactions of actors, linkages and relationships that characterise the whole system [26, 27]. Although qualitative models lack the capacity for quantitative simulations that represent how systems change over time, they are a useful ‘snapshot’ of systems that can aid in understanding complex problems and exploring potential leverage points for intervention and for systems change [4, 25, 28]. These models serve as a starting point for engagement between multiple stakeholders to sift out major issues, promote inquiry and challenge preconceived ideas [15, 29, 30]. Some have suggested that the power of qualitative modelling lies in encouraging decision-makers to avoid blind spots and to take action [31].
Although systems change is a term often used to refer generally to different types of big picture initiatives intended to solve social problems, some scholars have offered more precise definitions [4, 19, 20, 32, 33]. Specifically, Foster-Fishman et al. submit that systems change “refers to an intentional process designed to alter the status quo by shifting and realigning the form and function of a targeted system” [19]. Various theoretical frameworks exist for understanding complexity and working towards systems change [4, 15, 19]. Foster-Fishman et al. [19] use insights from their work in community development to outline detailed steps for defining and assessing the systemic nature of a problem. These steps culminate into a process for identifying feasible levers for change within the patterns that have been uncovered. Rwashana et al.’s [15] revised dynamic synthesis methodology begins with a qualitative research approach – using interviews and surveys – to gain a deeper understanding of the complex problem of interest in order to then start working towards systems change.
Systems thinking is gaining increased attention in the field of public health, where interventions and policies often fail to adequately take into account features of dynamic complexity, resulting from a combination of the diseases or conditions themselves and the systems in which they are embedded, that make public health challenges so difficult to solve [7, 15, 26, 34]. Because key challenges in public health are fundamentally systems problems, it is common for well-intended interventions to have counterintuitive and unintended negative consequences [18, 35]. In the public health context, systems have been defined as the interconnected sets of actors, activities and settings that jointly produce a health outcome [19, 25]. In 2009, WHO published a report making the case that, due to the complexity inherent to health systems, “every intervention, from the simplest to the most complex, has an effect on the overall system, and the overall system has an effect on every intervention” [27]. Thus, this report and subsequent publications argue that systems thinking has enormous potential to help decipher health system complexity and to design effective responses that seek to account in a holistic manner for the unpredictability of operating within this context [5, 26, 34, 36, 37]. While not a panacea, systems thinking tools can be useful in addressing complex public health problems by identifying key blockages and challenges and in helping to consider the long-term consequences of our actions.
Various systems thinking approaches have been applied to complex public health issues. Researchers have developed quantitative system dynamics models to improve planning for chronic disease-related interventions focused on diabetes, cardiovascular disease and tobacco control [8, 18, 38, 39]. Similar models have been applied to understand the complexities of eradicating infectious diseases such as polio and, more recently, of stopping the Ebola virus outbreak in West Africa [40, 41]. Without incorporating quantitative simulations, others have applied qualitative tools (i.e. causal loop diagramming) to illustrate the underlying dynamics of a variety of disease- or condition-specific interventions, such as improving newborn health or increasing vaccination rates, as well as health system strengthening interventions such as efforts to build resilient health systems, implement innovative financing mechanisms and assess programme sustainability [15, 28, 31, 42,43,44]. Despite the growing interest in systems thinking and the potential it holds for improving public health, there remains a need for additional documented, practical attempts at utilising systems thinking approaches to address real-world public health problems in ways that bring together diverse perspectives to influence policy and practice [19, 35]. A recent review found that a large proportion of public health articles drawing on systems methodologies were commentaries or calls for the application of these methods to public health [36]. The same review suggests that qualitative modelling techniques, such as the approach we apply in this study, are likely to be the most useful addition to public health.
As a complex public health problem for which the global health community often focuses on a narrow set of interventions, NTDs represent an ideal case study for the practical application of systems thinking. NTDs encompass 20 bacterial and parasitic infections that continue to represent a major disease burden in many parts of the world [45]. These diseases are closely associated with poverty, with the majority of the burden in sub-Saharan Africa and among the poor in middle-income countries [46, 47]. It is estimated that, annually, these diseases cause approximately 350,000 deaths and are responsible for 27 million disability-adjusted life years lost [48]. The focus of global NTD control and elimination efforts has largely been on the five NTDs that can be prevented through preventive chemotherapy medicines distributed via mass drug administration (MDA), namely lymphatic filariasis, onchocerciasis, soil-transmitted helminths, schistosomiasis and trachoma [49]. NTDs have generated significant attention from aid agencies and philanthropists in part because NTD control and elimination is widely seen as one of the best buys in global health, with effective MDA interventions in many circumstances costing less than US$0.50 per person per year [48, 49].
Although NTDs are often portrayed as a simple problem with known and easily implementable solutions (i.e. preventive chemotherapy drugs), many complex challenges have yet to be fully understood and addressed in order for countries to reach the ambitious 2020 NTD ‘end goals’ that were agreed upon by the World Health Assembly in 2013 [48]. Achieving these goals will require coordination between multiple actors engaged in numerous interrelated projects, which include changing attitudes, perceptions and practices of multiple stakeholders [15]. For example, despite significant financial and in-kind contributions, there is still an estimated US$200 million gap in annual funding needed to reach global NTD targets [50]. The level of political priority accorded to NTDs remains relatively low, particularly at the country level, compared to many other global health issues [51]. High-burden countries often lack the capacity to manage complicated supply chains and deliver available treatments, which creates a situation where the availability of donated drugs can outstrip country capacity to deliver them [52, 53]. Comorbidities exist with other diseases that make MDA interventions harder to implement in certain geographic areas [54]. Additionally, many NTD activities continue to be carried out in siloes rather than being integrated within country health systems and with donor programmes for other diseases and development priorities (e.g. water and sanitation) [55]. These represent a few of the various reasons why NTDs are a complex problem that will require learning on behalf of all stakeholders to generate additional, innovative solutions.
Our study seeks to encourage the use of systems thinking in public health by demonstrating how a systems thinking approach – in the form of qualitative modelling – can be applied to global NTD control and elimination efforts. In addition to focusing at the global level, our study looks at Nigeria as an example country. Nigeria has the highest burden of NTDs among African countries, with over 130 million people requiring preventive chemotherapy treatment annually [56]. Nigeria also receives a large amount of donor funding for NTDs, leading to significant programmatic complexity due to large numbers of domestic and international organisations involved in NTD control and elimination efforts in the country [57,58,59]. The overall aim of this study is to better discern the complexity of the global NTD system in order to identify and act on leverage points – “places within a complex system where a small shift in one thing can produce big changes in everything” [60] – to catalyse progress towards ending NTDs. Drawing on systems theory, the specific research questions that drive the study and frame our approach are (1) in which ways, if any, are NTDs a systemic or complex problem? (2) What leverage points for systems change exist within the global movement to end NTDs?
To address the study objectives, we developed a conceptual framework for systems change (Table 1) based on systems thinking theory and drawing heavily on Foster-Fishman et al.’s [19] framework as well as elements of the dynamic synthesis methodology framework used by Rwashana et al. [15].