NATIONAL INCOME ACCOUNTING
This refers to the measuring of the total flow of output (goods and services) and of the total flow of inputs (factors of production) that pass through all of the markets in the economy during the same period.
To see exactly what national income includes, how it is measured, and what it can tell us, we start with economic models: By economic models we mean:
A simplification of a real world or a practical situation aimed at explaining that situation within a set of assumptions.