Definition of Investment

The economist’s definition of investment is precise and differs from the way we often use the word in everyday speech. Specifically, economists do not use the term to mean the purchase of financial assets, such as stocks and bonds. Most of the time when we talk about investment in this book, we are referring to business fixed investment—the production of new physical capital goods. Inventory investment is a special category of investment that we explain in Section 7.3.2 “Inventory Investment”. As a rough rule of thumb, consumption spending is carried out by households, and investment spending is carried out by firms. But there is one important exception: new residential construction is included in investment. A new house purchased by a household is treated as investment, not consumption. Government purchases include all purchases of goods and services by the government. We include in our definition of “government” local as well as national government activity. In the United States, this means that we collapse together federal, state, and local governments for the purpose of our analysis. This component of spending refers only to purchases of goods and services, not to transfers. So, if the federal government buys aircraft from Boeing or the local police department buys a fleet of Volvos, these are included in government purchases. However, a transfer you receive from the government—say, because you are unemployed and are being paid unemployment insurance—is not counted in GDP. (Of course, if you then use this income to purchase goods and services, that consumption is part of GDP.) Net exports simply equal exports minus imports. They are included because we must correct for the expenditure flows associated with the rest of the world. Some spending in the economy goes to imported goods, which is not associated with domestic production.