why are both life expectancy and quality of life used to evaluate overall health?

Both life expectancy and quality of life are used to evaluate overall health because they provide complementary perspectives on health status. Life expectancy measures the average length of time a person is expected to live at a given age, capturing the quantity of life. Quality of life, particularly health-related quality of life, reflects an individual's overall well-being, including physical, mental, and social aspects of health, thereby addressing the quality or experience of living rather than just longevity. Using both measures together offers a more comprehensive evaluation of health. Life expectancy alone does not account for the health conditions or disabilities a person might experience during their lifetime. Quality of life measures help to capture these important factors by assessing how health conditions and treatments impact daily functioning, well-being, and personal expectations. Together, these metrics provide insight into not only how long people live but also how well they live, which is critical for healthcare decision-making, policy development, and evaluating the effectiveness of health interventions.