Which standardized metric of output is used to gauge the size and market potential of an economy?

The standardized metric of output used to gauge the size and market potential of an economy is the Gross Domestic Product.

Explanation:

The Gross Domestic Product is the value of goods and services that are

produced in a country in a certain time and it is consider an important indicator to analyze the state of a country's economy. The value of the goods and services produced is considered the size of the economy.

Also, as the GDP is an indicator of how the economy is doing, businesses tend to use it to predict if the sector will grow or not.