The three pillars of universal health coverage are population coverage, service coverage, and financial protection. In practical terms, they answer three questions every health system must face: who is covered, what services are included, and how much people pay out of their own pockets when they get sick. The World Health Organization visualizes these pillars as the three axes of a cube, and the goal of any country pursuing universal health coverage is to extend all three dimensions simultaneously so that everyone can access the care they need without being driven into poverty.
The WHO Cube and How the Pillars Relate
The most recognized way to picture these three pillars comes from the WHO’s “Cube Diagram,” which has been widely used in global health policy since the early 2010s. The cube’s three axes represent the services covered by pooled funds, the population covered, and the proportion of costs covered.1PubMed. Disaggregating the Universal Coverage Cube: Putting Equity in the Picture These dimensions are sometimes labeled differently depending on the source. One framing calls them depth, breadth, and height: what treatments to provide (depth), what proportion of the population to include (breadth), and what price patients face (height).2PubMed Central. Squaring the cube: Towards an operational model of optimal universal health coverage Another phrasing, from the WHO’s own bulletin, puts it as expanding the array of health services covered, including more people in systems of health financing, and reducing out-of-pocket spending so that people are not impoverished by seeking care.3PubMed Central. Accelerating action towards universal health coverage by applying a gender lens
The important thing about the cube is that no single pillar can stand alone. A system that covers 100 percent of the population but only for a narrow set of services leaves people exposed when they develop conditions outside that package. A system offering generous services to a small privileged group while millions remain uninsured is not universal. And a system that technically covers everyone for everything but charges crippling co-payments at the point of care might as well not exist for the poorest families. The three pillars have to advance together, even if the balance between them shifts from country to country.
Population Coverage: Who Gets In
The first pillar asks a seemingly simple question: does everyone in the country have access to the health system? In practice, the answer is rarely a clean yes or no. Many countries enshrine the right to health care in their constitutions and pursue policies to enroll as many residents as possible in some form of health insurance or public coverage.4PubMed Central. Population Coverage to Reach Universal Health Coverage in Selected Nations: A Synthesis of Global Strategies But the people who fall through the gaps tend to be those who are hardest to reach: informal workers, rural populations, migrants, and the very poor.
Informal workers are a particularly stubborn challenge. In many low- and middle-income countries, a large share of the workforce operates outside the formal tax and employment systems. These workers do not have employer-sponsored insurance, and they often lack the stable income needed to pay regular premiums. Research across Southeast Asia found that countries with explicit political commitments toward universal health coverage and universalist approaches, meaning full subsidies and mandatory coverage rather than voluntary opt-in schemes, reached the highest rates of coverage for informal workers.5PubMed Central. Extending universal health coverage to informal workers: A systematic review of health financing schemes in low- and middle-income countries in Southeast Asia In contrast, systems that relied on voluntary premium payments from informal workers struggled with low enrollment and irregular contributions.
Indonesia’s experience illustrates the problem well. The country launched a national health insurance system (JKN) intended to cover the entire population, but many informal-sector members do not pay their premiums consistently. Studies have pointed to a combination of financial hardship, low insurance literacy, and dissatisfaction with service quality as reasons.6PubMed. Why Do Informal Sector Workers Not Pay the Premium Regularly? Evidence from the National Health Insurance System in Indonesia Recommended fixes include making it easier to apply for government subsidies, promoting insurance literacy, and improving the quality of care people actually receive when they show up at a facility.
Broader strategies for expanding population coverage have been catalogued across many countries. A systematic review found six main categories of policy tools: changing eligibility criteria, increasing public awareness, making premiums more affordable, using innovative enrollment strategies, improving health care delivery, and improving how insurance schemes are managed and organized.7Health Policy and Planning. Expanding health insurance coverage in vulnerable groups: a systematic review of options No single tool works everywhere, but the pattern is clear: passive enrollment systems leave too many people behind.
Service Coverage: What Is Included
The second pillar concerns the depth of coverage. Even if a country manages to enroll its entire population, the benefits are limited if the package of services is too narrow. This is where the concept of a “health benefits package” (HBP) comes in. An HBP is an explicit statement of what services a system will finance and provide, given its real-world constraints.8PubMed. Defining a Health Benefits Package: What Are the Necessary Processes? Defining this package is one of the most politically fraught tasks in health policy because it forces governments to say, out loud, what is in and what is out.
Countries approach this differently. Some use formal health technology assessment to evaluate the cost-effectiveness of specific treatments before adding them to the package. In practice, though, only a limited number of countries have successfully used tools like cost-effectiveness analysis and budget impact analysis in their benefits package design. Research examining processes in Armenia, Ethiopia, the Kyrgyz Republic, Lebanon, and Malawi found that limited local cost data was the biggest obstacle.9PubMed. The Use of Economic Evaluation Tools in Essential Health Benefits Package Selection for Universal Health Coverage A proposed workaround for low- and middle-income countries is a hybrid approach that sets different cost-effectiveness thresholds for different service platforms, such as primary care versus essential surgery, rather than applying a single threshold across all treatments.10PubMed. The Role of HTA for Essential Health Benefit Package Design in Low or Middle-Income Countries
Regardless of the method a country uses, a strong primary health care system is considered the backbone of service coverage. Universal health coverage depends on primary health care to provide the front-line services that catch the majority of health problems before they become expensive emergencies.11PubMed Central. Communities, universal health coverage and primary health care Public health and primary care are sometimes described as the cornerstones of any sustainable health system, and this should be reflected in both policy and professional education.12PubMed Central. Primary health care and public health: foundations of universal health systems
Financial Protection: Shielding People From Ruin
The third pillar is the one that hits closest to individual lives. Financial protection means that using health services does not push people into poverty. When people pay too much out of their own pockets, the consequences can be devastating. In Togo, roughly 5 percent of the population is estimated to be pushed into poverty solely because of out-of-pocket health payments.13PubMed Central. Catastrophic health expenditure and household impoverishment in Togo In Bangladesh, the picture is similar: out-of-pocket spending pushed an estimated 5.1 million people below the poverty line.14Health Policy and Planning. Catastrophic healthcare expenditure and poverty related to out-of-pocket payments for healthcare in Bangladesh—an estimation of financial risk protection of universal health coverage
The flip side is that well-designed insurance schemes can make a real dent. Turkey’s expansion of a non-contributory insurance scheme (the Green Card program) to the poor led to roughly a 33 percent reduction in total per-household out-of-pocket medical spending for beneficiaries. For people facing the largest health expenditures, the scheme cut catastrophic spending by close to 50 percent.15BMJ Global Health. Effects of expanding a non-contributory health insurance scheme on out-of-pocket healthcare spending by the poor in Turkey Thailand’s universal coverage policy, launched in 2002, also showed measurable declines in catastrophic health payments and poverty caused by medical costs.16PubMed. Payments for health care and its effect on catastrophe and impoverishment: experience from the transition to Universal Coverage in Thailand
Financial protection does not just mean lower co-payments, though. It also involves the structure of how money flows into the system. A cross-national study of 89 low- and middle-income countries found that for every additional $100 per capita per year in tax revenues, government health spending rose by about $10. But the type of tax mattered: taxes on capital gains, profits, and income were strongly associated with higher government health spending, while consumption taxes on goods and services showed no significant link.17PubMed Central. Financing universal health coverage–effects of alternative tax structures on public health systems: cross-national modelling in 89 low-income and middle-income countries In countries with low tax revenues, that additional tax income substantially increased both the proportion of births attended by skilled health workers and the extent of financial protection for the population.
Trade-Offs and Ethical Boundaries
Because no country has unlimited resources, expanding one pillar sometimes means constraining another, at least temporarily. A government might cover a larger share of the population but offer a thinner set of services. Or it might offer comprehensive services to a smaller group while leaving others uninsured. These trade-offs are unavoidable, but some are considered ethically unacceptable. Health policy ethicists have argued, for example, that expanding coverage for low-priority services like coronary bypass surgery before securing universal access to high-priority services like skilled birth attendance or treatment for easily preventable childhood diseases is one such unacceptable trade-off.18PubMed Central. Ethical Perspective: Five Unacceptable Trade-offs on the Path to Universal Health Coverage
This framing matters because the cube metaphor can make it seem like all movement along any axis is equally valuable. It is not. A health system that prioritizes the wrong services or covers the wrong population segments first can entrench inequality even as it appears to be progressing toward universal coverage.
Quality as a Missing Dimension
One criticism of the three-pillar framework is that it says nothing about whether the services people receive are actually good. You can cover everyone, include a wide range of services, and charge nothing at the point of care, but if the quality of that care is poor, the results will be disappointing. A systematic analysis across 137 countries found that universal health coverage for conditions targeted by the Sustainable Development Goals could avert about 8.6 million deaths per year, but only if the expansion of service coverage is accompanied by investments in high-quality health systems.19The Lancet. Mortality due to low-quality health systems in the universal health coverage era: a systematic analysis of amenable deaths in 137 countries
This is not a minor footnote. In many low- and middle-income settings, people die not because they lacked access to a health facility but because the facility they reached could not provide effective treatment. Investing in patient-centered health systems that deliver high-quality services is essential to ensuring that limited health resources are used efficiently.20International Journal for Quality in Health Care. Measuring quality of care for universal health coverage in the Western Pacific Some researchers and policymakers have pushed for quality to be treated as a de facto fourth pillar, or at least as a lens applied across the other three.
How Progress Gets Measured
Tracking whether countries are actually advancing on these pillars is its own challenge. The WHO developed a UHC service coverage index using 16 tracer indicators spanning reproductive and child health, infectious diseases, noncommunicable diseases, and service capacity. Data for 183 countries were compiled from UN agency estimates and national submissions.21PubMed. Monitoring universal health coverage within the Sustainable Development Goals: development and baseline data for an index of essential health services This index is the basis for the Sustainable Development Goal indicator on UHC service coverage.
More recent work has pushed toward measuring “effective coverage,” which accounts not just for whether a service exists but whether it works well enough to produce health gains. A systematic analysis for the Global Burden of Disease Study 2019, covering 204 countries from 1990 to 2019, developed an effective coverage framework and found that it generally outperformed other UHC service coverage indices from the WHO and the World Bank in tests of validity.22The Lancet. Measuring universal health coverage based on an effective coverage framework for 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019 The shift toward effective coverage metrics reflects the growing recognition that counting services on paper is not the same as counting health outcomes in practice.
Thailand as a Real-World Example
Thailand is one of the most studied examples of a country that moved rapidly toward universal health coverage. In 2002, it launched the Universal Coverage Scheme, and by 2015 three public insurance schemes covered about 98.5 percent of the population. Evidence shows high levels of service coverage, strong financial protection, and low unmet health care need.23PubMed. The Political Economy of UHC Reform in Thailand: Lessons for Low- and Middle-Income Countries The reform’s success has been attributed to long-standing preparation by health system reformers, civil society mobilization, and political actors who seized a policy window when conditions aligned.24Discover Public Health. Thailand’s universal health coverage reform as a policy process roadmap for countries pursuing bold health system change
But the path was not smooth. The reform team had to overcome resistance from the budget bureau, which lost discretionary power under the new financing arrangements, and from parts of the Ministry of Public Health, which clashed with the newly created National Health Security Office over governance. Thailand’s experience suggests that technical preparation matters, but so does managing the politics. A reform team that can generate and use evidence to guide decisions can overcome opposition, even from entrenched interests.
Resilience Under Crisis
The COVID-19 pandemic stress-tested the three pillars everywhere. A multi-country study argued that the pillars of population coverage, service coverage, and financial protection proved even more crucial during the pandemic, because they determined whether vulnerable individuals could access testing, treatment, isolation, and vaccines without financial consequences.25The Lancet Global Health. Resilient health financing for health emergencies and universal health coverage: a multi-country comparative study of the COVID-19 pandemic Countries with weaker coverage structures before the pandemic were more likely to see people forgo care or be financially devastated by it.
Building a resilient health system turns out to require many of the same ingredients as building universal coverage: redistributing health workers to where they are needed, shifting tasks from scarce specialists to more available providers, using results-based financing, and maintaining high political commitment. A systematic review found that community-based response planning and multi-sector collaboration were critical enablers, while poor surveillance, weak leadership, and income inequality were major obstacles.26PubMed Central. Building a resilient health system for universal health coverage and health security: a systematic review In Senegal, local health insurance units adapted during COVID-19 by introducing electronic payments and using social networks to communicate with members and raise funds, showing that smaller-scale innovations can absorb shocks even in resource-limited settings.27BMJ Global Health. The resilience of two departmental health insurance units during the COVID-19 pandemic in Senegal
The Private Sector’s Role
In many low- and middle-income countries, the private sector is a major provider of health financing, medicines, and services. Universal health coverage cannot be achieved without engaging these private actors, but engagement is often fragmented. Weak oversight leads to inefficiencies, poor quality, and financial hardship for patients.28PubMed Central. The private sector and universal health coverage The recommended approach is for ministries of health to strengthen governance in three areas: formulating national health policies that explicitly include the private sector, establishing effective regulatory frameworks and transparent contracting, and creating platforms for ongoing dialogue and accountability between public and private stakeholders.
This is particularly relevant for the service coverage pillar. In countries where private providers deliver a large share of care, ignoring them when designing benefits packages means that the official package may not reflect what people actually use. If a government subsidizes only public facilities while most of the population visits private clinics, the coverage on paper diverges sharply from coverage in reality.
Subnational Inequality and Decentralization
Even within a single country, the three pillars can look very different depending on where you live. Decentralization of health financing, which many countries have adopted, can create new equity problems. When health funding is pooled at a local rather than national level, the cross-subsidization between richer and poorer regions shrinks. Evidence from Italy, Spain, China, and Ivory Coast suggests that fiscal decentralization has some positive effects on infant mortality, but it can also decrease health care resources and access in poorer areas, widening geographic disparities.29PubMed Central. Fiscal federalism vs fiscal decentralization in healthcare: a conceptual framework
A study of subnational fiscal autonomy in China found that greater fiscal autonomy for local governments had a positive effect on equity in health care resource allocation, but only up to a point. Beyond a certain threshold of regional wealth, the equalizing effect faded and became statistically insignificant.30Frontiers in Public Health. Fiscal autonomy of subnational governments and equity in healthcare resource allocation: Evidence from China In areas with aging populations and higher dependency ratios, local fiscal autonomy continued to strengthen equity, likely because those regions had stronger political incentives to invest in health. The lesson is that decentralization is not inherently good or bad for universal health coverage; what matters is whether national mechanisms exist to redistribute resources toward regions that cannot generate enough revenue on their own.
Aging Populations and the Pressure on All Three Pillars
Population aging and the rising burden of noncommunicable diseases are putting sustained pressure on universal health coverage in countries at every income level. Sub-Saharan Africa and other low- and middle-income regions face a particularly difficult version of this challenge because the growth in chronic diseases like diabetes, cardiovascular disease, and cancer is happening alongside persistent infectious disease burdens. Without serious action, the targets of reducing premature mortality from noncommunicable diseases by a quarter by 2025, and by a third by 2030, are likely to be missed. Strengthening universal health coverage, alongside economic empowerment, public-private partnerships, and public education on risk factors, has been identified as essential to making any progress.31Oxford Academic (The Gerontologist). Aging and the Rising Burden of Noncommunicable Diseases in Sub-Saharan Africa and other Low- and Middle-Income Countries: A Call for Holistic Action
Chronic diseases strain all three pillars at once. They require a broader service package that includes long-term medications, regular monitoring, and specialized care. They increase the number of people who need coverage over extended periods rather than for acute episodes. And they drive up out-of-pocket costs, particularly for medicines that must be taken indefinitely. Countries that designed their health benefits packages primarily around maternal and child health or infectious diseases are now scrambling to expand service coverage without blowing up their budgets. The three pillars were always meant to be dynamic, not fixed targets, and the demographic pressures of the coming decades will test whether countries can keep expanding the cube or whether some faces start to cave in.