How the U.S. Public Health System Works: From Policy to Action

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The U.S. public health system is a complex network of government agencies, clinical care delivery systems, community-based organizations, private businesses, and other organizations working together to support Americans’ health and well-being.

To learn more, check out the infographic below, created by Ohio University’s Master of Public Health program.

How U.S. public health leaders use systems thinking to create policies that protect the public.

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The Components of the U.S. Public Health System

The various arms of the U.S. public health system work together to provide 10 basic services to the American people.

The Building Blocks of the U.S. Public Health System

The public health system is composed of federal agencies, government agencies (other than public health), clinical care delivery systems, STLTs (state, tribal, local, and territorial health departments), the media, community-based organizations, private and nonprofit associations, educational institutions, and private industries.

10 Essential Public Health Services

The recently updated 10 Essential Public Health Services (EPHS) is a three-stage framework created by the Centers for Disease Control and Prevention (CDC) to guide all public health activities and efforts to keep communities healthy.

During the assessment stage, public health leaders assess and monitor public health to determine not only how healthy a group of people is but also what factors are impacting that group’s ability to maintain good health. The second step is to investigate, diagnose, and address health hazards and root causes by confronting the factors negatively impacting the public’s ability to stay healthy.

At the policy development stage, public health leaders must effectively communicate health guidelines and strengthen, support, and mobilize communities and partnerships to ensure everyone receives the health care they need. They must also create, promote, and implement policies, plans, and laws designed to improve people’s health. The final step in this stage is to utilize legal and regulatory actions to protect public health.

The third stage of public health services, assurance, involves enabling equitable access to all people; improving and innovating through evaluation, research, and quality improvement; and building and maintaining a strong organizational infrastructure.

How the System Works Together to Solve Complex Public Health Crises

To effectively navigate and address health crises, public health leaders must utilize systems thinking.

What Is Systems Thinking?

Systems thinking is the recognition that better public health requires a deep understanding of the interlocking networks that make up the U.S. public health system. These networks include clinics and hospitals, as well as patient support groups and community organizations.

5 Important Steps in Systems Thinking

The first step in systems thinking is to identify systems problems, which are dynamic, interconnected/interdependent, and difficult to describe. This step is necessary to understand a problem’s causes, pursue a policy option, and engage with stakeholders and decision-makers, which may lead to more effective solutions.

The second step involves thinking dynamically and viewing public health issues as patterns of behavior or health outcomes over time, rather than static points; this provides a broader perspective of the issue.

During the third step, public health leaders must get operational and use “stock and flow” diagrams to map a system and identify levels that can be adjusted to improve performance. Stocks represent accumulations — such as the number of beds in a hospital, positive cases, or fatalities — and can be measured at any point in time. Flows are actions that fill or drain stocks over time, such as admitting or discharging patients from a hospital.

The fourth step is to expand the boundary of inquiry to help agencies anticipate unintended consequences and increase the likelihood of considering a larger set of relevant relationships, which increases the possibility of developing solutions. The fifth step is to look for feedback, which reveals the consequences — intended and unintended — of changes to health systems.

3 Categories of Problems in Public Health

Public health leaders face simple, complicated, and complex public health problems. They can use best practices and evidence-based guides to address simple problems.

Using “good enough” knowledge can lead to solutions to complicated problems. Causal structures are difficult to predict, which can create complicated problems, and public health leaders need to map the various interactions and parts of a system before identifying a solution.

When addressing complex health problems, public health leaders need to adopt a holistic approach because the interactions between the parts cannot be reduced to the functions or intended roles of the individual parts.

Systems Thinking in Action

Finding solutions to complex problems requires systems to work together. The following examples illustrate how systems thinking has been successfully employed.

Forecasting Extreme Weather

People can open a weather app and check the forecast, but that seemingly simple forecast is the result of complex data modeling that requires multiple levels of collaboration among oceanographers, physicists, atmospheric chemists, and geographers.

As forecasting becomes more accurate further in advance, it will allow for even more informed decision-making — potentially saving lives. Extreme weather can hurt people’s health by causing stress, food insecurity, waterborne diseases, air pollution, wildfires, and floods.

Predicting and Responding to Pandemics

Recognizing the risk of outbreaks and moving to minimize them, public health agencies employ various models that incorporate systems thinking. The Models of Infectious Disease Agent Study (MIDAS) brings experts together to model disease spread, prediction systems, and response strategies. This kind of collaboration can help save lives through facilitating rapid communication, massive data collection, transdisciplinary science, and complex modeling.

The Key to Effective Public Health Leadership

A systems-thinking approach empowers public health officials to create solutions that effectively address the health needs of all individuals, regardless of economic or social status.


American Journal of Preventive Medicine, “Systems Thinking to Improve the Public’s Health”
American Medical Association, “Why You Need to Be a Systems Thinker in Health Care”
Centers for Disease Control and Prevention, 10 Essential Public Health Services
Centers for Disease Control and Prevention, Climate Effects on Health
Centers for Disease Control and Prevention, Components of Public Health System Description
Centers for Disease Control and Prevention, How Do You Identify a Systems Problem?
Centers for Disease Control and Prevention, Why Get Operational?
Centers for Disease Control and Prevention, Why Expand the Boundary of Inquiry?
Centers for Disease Control and Prevention, Why Look for Feedback?
Centers for Disease Control and Prevention, Why Think Dynamically?
Healthline, “The Worst Outbreaks in U.S. History”
Monash Bioethics Review, “Systems Thinking and Ethics in Public Health: A Necessary and Mutually Beneficial Partnership”
Science News, “Improved Three-Week Weather Forecasts Could Save Lives From Disaster”
Systems, “Developing a Preliminary Causal Loop Diagram for Understanding the Wicked Complexity of the COVID-19 Pandemic”
Verywell Health, “The 10 Essential Public Health Services”