How can we measure human health?

There are many ways to measure human health, especially when considering whole populations. One potential metric is life expectancy, or how long groups of people are expected to live. Quality of life, or how well groups of people can fulfill their needs and wants, is another standard. 

Examining different rates of physical or mental illnesses, and how those rates change over time, can also give insight into human health. Looking at these trends can help scientists understand whether groups are getting more or less healthy over time.