Why It Matters
This is a handy primer to explain the differences between population health, population management, and other terms related to the Triple Aim.
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Populations, Population Health, and the Evolution of Population Management: Making Sense of the Terminology in US Health Care Today

By Niñon Lewis | Wednesday, March 19, 2014
Lewis Triple Aim

In the years since IHI first began developing the concept of the Triple Aim, what started as an ambitious ideal for system transformation has become a rallying cry at the policy level, a mission and strategy for many health systems, and a burning platform for new collaborations within communities. The idea that the successful health and health care organizations of the future will be those that can simultaneously deliver excellent quality of care, at lower total costs, while improving the health of their population is taking hold.

However, as IHI has pilot-tested the Triple Aim with nearly 150 organizations and coalitions around the world, and watched the natural diffusion of the framework within health care, it has become evident that some of the terminology used to talk about this concept needs clarification. What does IHI mean when we use terms such as "population," "population health," and "population management"?

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When embarking on a journey to achieve the Triple Aim, organizations and coalitions need to choose a relevant population to work with by answering the question, “For whom do we hold ourselves accountable for the Triple Aim?” The population chosen must make sense to the organization or coalition in all three dimensions of the Triple Aim: it must be clear how to deliver excellent care and improve health for the population, at lower total cost. Typically, organizations choose either discrete/defined populations or regional/community populations:

  • Discrete/defined populations are enterprise-level populations that make business sense. Typically, they are a group of individuals receiving care within a health system, or whose care is financed through a specific health plan or entity. Examples of a discrete population include employees of an organization, members of a health plan, all those within a practice patient panel, or all those enrolled within a particular ACO. The members of a discrete population can be known with some certainty.
  • Regional/community populations are inclusive population segments, defined geographically. People within a segment of a community population are unified by a common set of needs or issues, such as low-birth weight babies or older adults with complex needs. However, these individuals may receive care from a variety of systems or may be unconnected to care. They may or may not be insured. It is often difficult to enumerate the population with certainty. When addressing regional populations, we recommend selecting segments where better health care can make a significant contribution to achieving Triple Aim results.

Population Health

This term is used interchangeably with the term "health of a population." Here are a few details:

David Kindig, population health researcher, constructive critic of the Triple Aim, and IHI colleague, penned the following definition for population health, which IHI uses in our work:

Population health is defined as the health outcomes of a group of individuals, including the distribution of such outcomes within the group. These groups are often geographic populations such as nations or communities, but can also be other groups such as employees, ethnic groups, disabled persons, prisoners, or any other defined group.

While Kindig’s definition has been debated in both public health and health care circles since its first publication in 2003, its very articulation has sparked constructive discussion about what it means to address all of the broader factors that influence health, placing a specific focus on reducing or eliminating the inequity and disparities among various subpopulations, driven in part by social determinants of health.

The IHI Triple Aim team operationally defines the term “population health” by the measures we use, noted in the IHI White Paper, A Guide to Measuring the Triple Aim: Population Health, Experience of Care, and Per Capita Cost, including measures such as life expectancy; mortality rates; health and functional status; disease burden (the incidence and/or prevalence of chronic disease); and behavioral and physiological factors such as smoking, physical activity, diet, blood pressure, BMI, and cholesterol (as measured via a Health Risk Appraisal).

Population Management and the Evolution of Population Medicine

The rapid changes of the last five to seven years in policy-level decision making, payment structures, and provider alignment have shifted the focus from care provided and paid for at an individual level, to managing and paying for health care services for a discrete or defined population – an approach known as population management. The term population management should be clearly distinguished from population health (which focuses on the broader determinants of health). From what we have seen through our work at IHI, population management as presently practiced is best conceptualized as population medicine.

Population medicine, in this case, is the design, delivery, coordination, and payment of high-quality health care services to manage the Triple Aim for a population using the best resources we have available to us within the health care system. Much of the efforts today such as the Accountable Care Organization, risk stratification methods, patient registries, Patient Centered Medical Home, and other models of team-based care are all part of a comprehensive approach to population medicine. This is an excellent evolution for health care and an excellent place for health systems to be in. In many positive ways, Ed Wagner can be looked to as the father of population medicine, as his creation of the Chronic Care Model has helped move the culture in health care from reacting to the acute needs of patients to a proactive reorganization of health care delivery around the needs of populations.

Effective population management will require new partnerships among providers and payers, integrated data support, redesigned IT structures, a focus on non-traditional health care workforce, new care management models, and a shift from fee-for-service delivery to bearing financial

When Population Medicine Meets Population Health

As you begin to understand populations, the lines between a population management/medicine focus on health care services and a population health focus on the broader determinants of health become blurry with certain population segments. Consider, for example, the comprehensive care designs that serve the needs of your most complex, high-risk, and costly patients. The identification, understanding, and segmentation of your population; the redesign of services for that population; and the delivery of those services at scale require organizations to understand and address the broader social, environmental, and behavioral determinants of health in order to achieve better outcomes, improve the care experience, and control total cost.

Looking Ahead…

Whether you are working to understand how to deliver and pay for services at scale for a discrete or defined population, collaborating with other systems within an ACO, or extending your reach within the community to collaborate across sectors on a community-wide health issue, the frontier of the next 10 years for both population health and population management/medicine will be developing new collaboration and governance structures, new skills to assess and segment populations, new approaches for going to scale, and, most importantly, new approaches to address the moral imperative of understanding and reducing inequity in both health and health care.

IHI continues to help organizations on this journey to address the needs of discrete and community-wide populations to achieve the Triple Aim. We hope that being clear about the meanings of some of these terms will help you better understand the populations you serve.

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