[Isamu]

Inflation is the change in the Consumer Price Index, calculated by the US Bureau of Labor Statistics. They explain the difficulty in representing accurate cost of living:

https://www.bls.gov/cpi/questions-and-answers.htm

>The CPI frequently is called a cost-of-living index, but it differs in important ways from a complete cost-of-living measure. We use a cost-of-living framework in making practical decisions about questions that arise in constructing the CPI. A cost-of-living index is a conceptual measurement goal, however, and not a straightforward alternative to the CPI. A cost-of-living index would measure changes over time in the amount that consumers need to spend to reach a certain utility level or standard of living. Both the CPI and a cost-of-living index would reflect changes in the prices of goods and services, such as food and clothing that are directly purchased in the marketplace; but a complete cost-of-living index would go beyond this role to also take into account changes in other governmental or environmental factors that affect consumers' well-being. It is very difficult to determine the proper treatment of public goods, such as safety and education, and other broad concerns, such as health, water quality, and crime, that would constitute a complete cost-of-living framework. Since the CPI does not attempt to quantify all the factors that affect the cost-of-living, it is sometimes termed a conditional cost-of-living index.