Life expectancy upon reaching adulthood is also a comparison that is frequently done. The arrival of effective hygiene and medicine in the last ~150 years has had a very clear effect on those numbers (a 65 year old US person today can expect to live 6 or 7 years longer than their 1900 counterpart. That&#x27;s a 65 year old!).<p>I also think it&#x27;s tough to correctly estimate the impact of medicine on quality of life. A lot of things in medicine are so effective that we forget they exist (like correcting cleft palate or whatnot).