Equity in healthcare encompasses two distinct principles: horizontal equity (equal treatment for equal need — people with the same health condition should receive the same care regardless of income, race, or geography) and vertical equity (appropriately unequal treatment for unequal need — sicker people should receive more care). Health inequity is the systematic, avoidable, and unjust difference in health outcomes or healthcare access between population groups. Health economics measures equity through concentration indices (plotting the cumulative share of health or healthcare against the cumulative share of the population ranked by income), benefit incidence analysis (who actually receives publicly funded healthcare?), and decomposition of health inequalities into contributing factors. The distinction between inequality (any observable difference) and inequity (differences that are unfair and avoidable) is normative — it requires a value judgment about what differences are unjust.
Equity is a core value in health economics — distinct from efficiency and sometimes in tension with it. An efficient allocation maximizes total health from available resources; an equitable allocation ensures fair distribution of health and healthcare across population groups. A perfectly efficient system could concentrate all resources on the patients who benefit most per dollar, which might systematically favor the wealthy, educated, and urban populations who are easier and cheaper to treat. Equity constraints force the system to also serve hard-to-reach, expensive-to-treat, and disadvantaged populations.
Horizontal equity (equal treatment for equal need) is the most widely accepted equity principle. It means that two patients with the same condition should receive the same quality and timeliness of care regardless of income, insurance status, race, gender, geography, or other non-clinical characteristics. Violations are pervasive: studies consistently show that racial minorities receive less aggressive treatment for cardiac disease, less pain management, and lower-quality surgical care than white patients with identical conditions. Income-based disparities in access, wait times, and treatment quality are documented in every country, including those with universal coverage.
Vertical equity (appropriately unequal treatment for unequal need) requires that sicker people receive more care — a principle that sounds obvious but is violated when cost-sharing deters the poor and chronically ill from seeking care, when rural populations lack access to specialist services, or when insurance benefits are structured to favor healthy enrollees. Progressive financing (those with higher income contributing proportionally more) is a vertical equity principle applied to the funding side.
Measuring equity requires both data and normative choices. The concentration index is the standard tool: it plots the cumulative share of healthcare utilization (or health outcomes) against the cumulative share of the population ranked by income. A concentration index of zero indicates equal distribution; positive values indicate concentration among the rich; negative values indicate concentration among the poor. But raw utilization data must be adjusted for need — if the poor are sicker, equal utilization represents inequity (they need more care than they are receiving). The horizontal inequity index adjusts for need, revealing whether the system provides equal care for equal need or systematically favors particular income groups.