Advancing the Systems Science Paradigm in Public Health Through Intervention and Evaluation.

We change paradigms by building a model of the system, which takes us outside the system and forces us to see it whole. Donella Meadows, 2008, p. 164 SYSTEMS SCIENCE was identified as a novel approach in the field of public health 15+ years ago.1 Since then, it has slowly been accepted as an alternative scientific paradigm.2 This shift has occurred as researchers and practitioners started to focus on health outcomes as they emerge from the interconnections of diverse, multilevel factors that are dynamic and evolving, as opposed to discreet behaviors.3,4 Although systems-based frameworks such as social ecology and the social determinants of health are not new to the field, they are often used only to identify causal factors at different levels, as opposed to considering how causal factors are interconnected across levels to produce outcomes.5,6 Within this aim, researchers have begun to use systems science to investigate a wide variety of health issues, including obesity prevention, emergency response, tobacco control, and adolescent health, among other topics.7–10 Advancements in health equity have also encouraged researchers and practitioners to consider how structural components and root causes create health crises in marginalized populations.11 In recent years, systems science has become institutionalized in public health as renewed, stable funding has been allocated to support its implementation, and its principles have been embedded into supportive structures.12 Federal funders, such as the National Institutes of Health, sponsor systems-level research to improve community health outcomes.13 Accreditation and credentialing bodies, such as the Council on Education for Public Health, and the National Commission for Health Education Credentialing, have included systems thinking competencies in their training objectives.14 Although significant progress has been made, this shift to fully adopting systems science as a paradigm in public health is incomplete. Conceptual ideologies around systems approaches in health have advanced, but research and evaluation that assess systems-level change are not as developed. Frequently, methods of investigation still focus on individuals and use surveys or other interpersonal tools to assess behavior or perceptions of ecological factors, as opposed to evaluating interconnected outcomes at the policy, community, or organizational levels.15 To address this gap, Family and Community Health, along with the W.K. Kellogg Foundation, has commissioned a special issue on systems-level public health interventions and evaluations. The purpose of this commentary is to review how systems science is currently used in public health, suggest areas of improvement, and then review included articles' various techniques to intervene and evaluate complex health problems. UTILIZATION OF SYSTEMS SCIENCE IN PUBLIC HEALTH Frequently, the field of public health applies systems science as (1) a practice, (2) a method, and/or (3) a categorical term. As a practice, systems thinking techniques are used to understand and address complex problems.3 As a method, systems science quantifies outputs of multidimensional, complex interventions.16 As a categorical term, systems is used to describe large, multifaceted agencies working within and across departments, or teams, to address the needs of a subpopulation.3 Each application is useful and can be used to understand or intervene in the complex issues that persist in public health; however, they all operationalize the term system differently, as it pertains to their particular purpose. For example, in systems thinking, goals include understanding complexity, building group consensus around root causes, identifying opportunities for leverage, and intervening in a way that reduces the likelihood of unintended consequences.17 As a method, systems science uses various techniques (network analysis, agent-based modeling, system dynamics, etc) to simulate complex scenarios and attempt to quantify useful outputs that gauge the implementation and/or effectiveness of interventions.16 As a categorical term, health systems represent large ecosystems of institutions that aim to work within and across entities to provide quality services to a subpopulation.18 Commonalities across these applications exist. They all embrace the complex nature of health challenges and go beyond a traditional, reductionist approach to health.19 Each application also recognizes interconnectedness and the idea of feedback—a time-varying process by which a system's outputs are reincorporated or looped back into the system as input to reinforce or counterbalance its functioning.20 GAPS IN THE USE OF SYSTEMS APPROACHES IN PUBLIC HEALTH Because public health has endorsed the concept of systems as it applies to understanding and intervening, it is important to assess intervention outcomes at multiple levels to fully understand their impact. Intentional evaluation must be completed to thoroughly understand relationships between the socioecological and biological determinants of health, multifactorial pathways, and their dynamic outcomes. Systems methods such as agent-based models are one opportunity to assess complexity, feedback, and long-term outcomes; however, this type of modeling is often inaccessible to practitioners and researchers. Data scientists with specific skills are needed to construct these models, and many models lack necessary validation to ensure that they are good representations of the issues they are simulating.3 As a result, many researchers evaluate systems-level interventions using individual-level analysis, which does not accurately assess processes nor outcomes. The articles in this special issue provide alternative approaches to evaluate and create systems-level interventions. Authors utilize a diverse set of methods to evaluate multilevel systems interventions, offer insights into community engagement for systems approaches, and incorporate innovation into systems intervention design. In aggregate, this special issue provides researchers and practitioners with examples of how the field of public health is advancing in its use of systems approaches to address health inequity. MULTILEVEL EVALUATION APPROACHES TO EVALUATE SYSTEMS OUTPUTS Kunin-Batson et al21 use a multimethod approach to explore associations between childhood obesity and structural racism by quantifying neighborhood-level inequities, perceived discrimination, sociodemographic data, and medical records. The study's results reflect the emergent and sometimes reinforcing properties of systems—in this case, racism manifested and maintained through oppressive policies at the federal, state, and local levels. This work pushes public health research forward by evaluating the impact of neighborhood structural factors on childhood obesity. Devine et al22 assess the multifaceted, longitudinal nature of community power using data on policy and systems changes related to California's school-based Local Control Funding Formula. They argue that a systems thinking lens is necessary to fully capture the cumulative impact that policy and systems wins and losses can have on power building. The article details a 10-year longitudinal study that advances our understanding of how to capture indicators of a very complex dimension of community capacity. Garney et al23 use an innovative agent-based model to understand the potential impact of a community-level policy, Safe Routes to School, on cardiovascular disease outcomes, as well as its unintended consequences (eg, injury and death). The model breaks new ground by simulating multiple health outcomes and providing a realistic representation of policy impacts. This article presents a cost-effective, data-driven approach that can be applied to garner policy buy-in and support advocacy efforts at the local level. COMMUNITY ENGAGEMENT WITHIN SYSTEMS-LEVEL EVALUATIONS Decker and Wendel24 offer a systematic review summarizing peer-reviewed studies that apply participatory approaches of systems dynamics modeling to public health. They document benefits and limitations of participatory system dynamics, stressing the methods' accessibility, acceptability, and adaptability. Specific benefits include, but are not limited to, increased community engagement, decreased power imbalances, and the ability to convey complex problems to policymakers and community leaders. The review illustrates public health's growing interest in participatory system dynamics and argues the methods' potential to enhance health research and practice. Sattler et al25 present a brief report of their research that engaged diverse communities of youth voices in an evaluation of community- and school-based sexual health programming in the state of Washington. In partnership with youth, including Two Spirit / Lesbian, Gay, Bisexual, Transgender, Queer, Intersex, Asexual+ and Black, Indigenous and people of color communities, as well as 11 grant-funded community partners, the authors offer 6 innovative strategies for centering youth voices in all levels of development and implementation of programming, embracing holistic and culturally relevant approaches, and meaningful inclusion of 2SLGBTQIA+ experiences. The identified strategies address systemic challenges experienced by youth in accessing and experiencing sexual health care. INNOVATION IN SYSTEMS-LEVEL INTERVENTIONS Wilson et al26 discuss the consequences of the adolescent health evidence–based program list (endorsed by federal agencies) targeting individual-level outcomes and introduce a framework to develop systems-level programming. The Framework for Public Health Innovation was used to develop Confident Teen, an innovative approach addressing adolescent access to health care. The article describes the framework's primary factors and their connections—dissatisfaction with the status quo and space, process, and partnerships—providing a practical approach to apply systems principles in public health. Charles and colleagues27 designed and tested an innovative multilevel intervention, Pathways for Parents after Incarceration Program, which engages participants across different systems to address the complex needs of fathers following release from prison or jail. It incorporates intrapersonal, interpersonal, and organizational change mechanisms to increase supports that are protective factors to reentry outcomes.