Why are both life excpectancy and quality of life used to evaluate overall health?

Answer 1

Life expectancy is the number of years a man or a woman can be expected to live. In the 1800s, life expectancy averaged around 50 years but many children, teens, and young adults died before age 21, and some people lived at least into their 60s. With advances in healthcare and technology, life expectancy is around 80 years-- with slight differences for men and women-- and some people live to 90-100 years.

Quality of life is a complex set of factors that define how much "living" a person can freely enjoy and whether the person can freely participate in life. "Quality" must include how a person views their own life, but minus any depression that illness causes. Since "quality" is defined individually, there is no set guidelines for when "quality of life" is excellent, good, or poor. As an example, 2 people may experience about the same degree of physical chronic pain, but one person may feel their quality of life is acceptable while the 2nd person believes their life of pain is unacceptable. I once overheard a nurse comment (inappropriately) to a patient that the nurse did not understand "why you haven't already just ended it--committed suicide" because the patient suffered greatly and could barely walk. The patient said, "Because I still have living to do."

When a person must deal with debilitating illness or pain, especially for decades, someone could say that person's quality of life is poor/bad. But, to accurately assess "quality", the patient must give their opinions about this topic. Most people would rather continue living however they can, despite pain or disability, than to contemplate the alternative-- the finality of death.