Defining health may seem simple, but its meaning can vary depending on context and perspective. Over the last decade, the concept of "population health" has gained prominence, expanding the idea of health beyond individuals to encompass entire communities.
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The World Health Organization (WHO) offers a well-known and comprehensive definition of health [1]:
"A state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity"

This definition is appealing because it focuses on positive aspects of well-being, not just the absence of disease. However, it has faced some criticism and is not universally adopted in all healthcare systems.

In healthcare decision-making, health and health systems performance are often evaluated based on two key principles:

  • Goodness: How well a health system meets people’s expectations and achieves the best overall health for the population.
  • Fairness: How the health system serves everyone equally without discrimination, reducing health disparities between individuals and groups.

[1] Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19-22 June, 1946; signed on 22 July 1946 by the representatives of 61 States (Official Records of the World Health Organization, no. 2, p. 100) and entered into force on 7 April 1948. Available at:  https://apps.who.int/gb/bd/PDF/bd47/EN/constitution-en.pdf