- Like the accounts of a business, national income accounts have two sides: a product side and an income side. The product side measures production and sales. The income side measures the distribution of the proceeds from sales.
- On the product side are two widely reported measures of overall production: gross domestic product (GDP), and gross national product (GNP). They differ in their treatment of international transactions.
- GNP includes earnings of U.S. corporations overseas and U.S. residents working overseas; GDP does not. Conversely, GDP includes earnings in the United States of foreign residents or foreign-owned firms; GNP excludes those items. For example, profits earned in the United States by a foreign-owned firm would be included in GDP but not in GNP.
- GDP includes only currently produced goods and services. It is a flow measure of output per time period—for example, per quarter or per year—and includes only goods and services produced during this interval.
- Only the production of final goods and services enters GDP. Goods used to produce other goods rather than being sold to final purchasers—what are termed intermediate goods —are not counted separately in GDP.
- However, two types of goods used in the production process are counted in GDP:
- The first is currently produced capital goods —business plant and equipment purchases. Such capital goods are ultimately used up in the production process, but within the current period, only a portion of the value of the capital good is used up in production. (In GDP, the whole value of the capital good is included as a separate item. In a sense, this is double counting because, as just noted, the value of depreciation is embodied in the value of final goods. At a later point, we will subtract depreciation to construct a net output measure)
- The other type of intermediate goods that is part of GDP is inventory investment — the net change in inventories of final goods awaiting sale or of materials used in the production process. These additions should be counted in the current period as they are added to stocks so that the timing of national product is defined correctly
- Consumer-durable goods (TV, freeze)
- Non-durable consumption goods (Food items, clothing)
- Consumer services (Medical service, haircut)
- Business fixed investments (for purchase of capital goods)
- Residential construction investments
- Inventory investments
- The foreign sector will be omitted. This makes GNP and GDP are thus equal. The terms GNP and GDP are used interchangeably except where we see the foreign sector.
- We assume that national income and national product or output are the same. The terms national income and output are used interchangeably throughout.
- Depreciation is ignored (except where explicitly noted). Therefore, the gross and net national product is identical.
- We assume that all corporate profits are paid out as dividends; there are no retained earnings or corporate tax payments. We assume that all taxes, including Social Security contributions, are assessed directly on households.
- Net Tax Payment = Tax payment - Government Transfers
- Personal disposable income(YD) = National Income(Y) - Net Tax Payment (T)
- GDP(Y) = C + Ir + G (The subscript ( r ) on the investment term is includedbecause we want to distinguish between this realized investment total that appears in the national income accounts and the desired level of investment spending)
- By ignoring interest paid to business: YD = Y - T = C + S (People use money to consumption and saving only)
- From 8: Y = C + S + T
- Hence GDP(Y) = C + Ir + G .= Y .= C + S + T
- This identity states that expenditures on GDP (C+ Ir + G) by definition equal dispositions of national income (C + S + T)