Preston Curve Links Income and Life Expectancy

June 4, 2024

The Preston Curve is a well-known empirical relationship that shows how the life expectancy of a country’s people is related to its per capita income. The sociologist Samuel H. Preston first noticed the curve in 1975. It shows that people in richer countries tend to live longer than people in poorer countries.

What is Preston Curve?

One simple but powerful trend that Preston’s research shows is that as a country gets richer, its people live longer. This connection is usually explained by the fact that people in wealthier countries have better access to health care, better schooling, better nutrition, and cleaner living conditions. By comparison, India’s average life expectancy rose from 32 years in 1947 to over 66 years by 2011, at the same time that the country’s per head income rose from ₹9,000 to about ₹55,000.

Limitations of Growth in Life Expectancy

When a country’s economy is just starting to grow, life expectancy can go up by a lot. But after a certain level of income per head, this effect tends to stop. Given this linear trend, it seems that life expectancy can only be raised so far, even if more money is made. The fact that life expectancy goes down as wealth goes up shows how complicated the relationship is between economic growth and human health.

Broader Implications and Criticisms

The Preston Curve can be used for more than just life expectancy. It can also be used for other indicators of development, like the rates of infant and maternal mortality and the general quality of healthcare and education. People have used the curve to argue that economic progress is the best way to improve these measures of human development. But some people say that many of the benefits, like longer life span, may come from better technology and more money spent on public health, not from the economy growing directly. This criticism talks about examples of countries with low incomes that have high life expectancy because they have access to new medical tools and can share their knowledge with other countries. So, critics say that even though economic growth is good, it shouldn’t be seen as the only way to make people better off. They stress the importance of strategic public spending and working together around the world to share technologies. In conclusion, the Preston Curve gives us a basic understanding of how economic status affects life expectancy. However, it also opens the door to a more in-depth conversation about the many aspects of development and the ways that technology, policy, and working together across borders can improve people’s lives.

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