Learning Objectives

Learning Objectives

By the end of this section, you will be able to do the following:
  • Identify the components of gross domestic product on the demand side and on the supply side
  • Evaluate how gross domestic product is measured
  • Contrast and calculate gross domestic product, net exports, and net national product

Macroeconomics is an empirical subject, so the first step toward understanding it is to measure the economy.

How large is the U.S. economy? The size of a nation’s overall economy is typically measured by its gross domestic product (GDP), which is the value of all final goods and services produced within a country in a given year. The measurement of GDP involves counting the production of millions of different goods and services—smartphones, cars, music downloads, computers, steel, bananas, college educations, and all other new goods and services—produced in the current year, and summing them into a total dollar value. This task is straightforward: take the quantity of everything produced, multiply it by the price at which each product sold, and add up the total. In 2014, the U.S. GDP totaled $17.4 trillion: the largest GDP in the world.

Each of the market transactions that enter into GDP must involve both a buyer and a seller. The GDP of an economy can be measured either by the total dollar value of what is purchased in the economy, or by the total dollar value of what is produced. There is even a third way, as we will explain later.

GDP Measured by Components of Demand

GDP Measured by Components of Demand

Who buys all of this production? This demand can be divided into four main parts: consumer spending (consumption), business spending (investment), government spending on goods and services, and spending on net exports. (See the following Clear It Up feature to understand what is meant by investment.) Table 5.1 shows how these four components added up to the GDP in 2014. Figure 5.4 (a) shows the levels of consumption, investment, and government purchases over time, expressed as a percentage of GDP, while Figure 5.4 (b) shows the levels of exports and imports as a percentage of GDP over time. A few patterns running through each of these components are worth noticing. Table 5.1 shows the components of GDP from the demand side. Figure 5.3 provides a visual of the percentages.

Components of GDP on the Demand Side (in Trillions of Dollars) Percentage of Total
Consumption $11.9 68.4%
Investment $2.9 16.7%
Government $3.2 18.4%
Exports $2.3 13.2%
Imports –$2.9 –16.7%
Total GDP $17.4 100%
Table 5.1 Components of U.S. GDP in 2014: On the Demand Side (Source: http://bea.gov/iTable/index_nipa.cfm)
This pie chart shows the percentage of components of U.S. GDP on the demand side as follows: Consumption: 68.4% Investment: 16.7% Government: 18.4% Exports: 13.2% Imports: −16.7%
Figure 5.3 Percentage of Components of U.S. GDP on the Demand Side Consumption makes up over half of the demand side components of the GDP. (Bureau of Economic Analysis, 2013).

Clear It Up

What is meant by the word investment?

What do economists mean by investment, or business spending? In calculating GDP, investment does not refer to the purchase of stocks and bonds or the trading of financial assets. It refers to the purchase of new capital goods; that is, new commercial real estate (such as buildings, factories, and stores) and equipment, residential housing construction, and inventories. Inventories that are produced this year are included in this year’s GDP—even if they have not yet sold. From the accountant’s perspective, it is as if the firm invested in its own inventories. Business investment in 2014 was almost $3 trillion according to the Bureau of Economic Analysis (BEA) (2013).

This is a line graph with parts a and b. Part a shows the demand from consumption, investment, and government from the year 1960 to 2014. In 1960, the graph starts out at 61.0% for consumption. It remains fairly steady around 60% until 1993, when it is at 65%.  By 2014, it is at 68.5%. In 1960, the graph starts out at 22.3% for government. It remains steady around 20%, and by 2014, it is at 18.2%. In 1960, the graph starts out at 15.9% for investment. It rises gradually to 20.3% in 1978, then generally go
Figure 5.4 Components of GDP on the Demand Side (a) Consumption is about two-thirds of GDP, but it fluctuates relatively little over time. Business investment hovers around 15 percent of GDP, but it increases and declines more than consumption. Government spending on goods and services is around 20 percent of GDP. (b) Exports are added to total demand for goods and services, while imports are subtracted from total demand. If exports exceed imports, as in most of the 1960s and 1970s in the U.S. economy, a trade surplus exists. If imports exceed exports, as in recent years, then a trade deficit exists. (Bureau of Economic Analysis, 2013).

Consumption expenditure by households is the largest component of GDP, accounting for about two-thirds of the GDP in any year. This tells us that consumers’ spending decisions are a major driver of the economy. However, consumer spending is a gentle elephant: When viewed over time, it does not jump around too much.

Investment expenditure refers to purchases of physical plants and equipment; primarily by businesses. If a chain of coffee shops builds a new store, or a delivery service buys robots, these expenditures are counted under business investment. Investment demand is far smaller than consumption demand, typically accounting for only about 15–18 percent of GDP, but it is very important for the economy because this is where jobs are created. However, it fluctuates more noticeably than consumption. Business investment is volatile: New technology or a new product can spur business investment, but then confidence can drop and business investment can pull back sharply.

If you have noticed any of the infrastructure projects (new bridges, highways, airports) launched during the recession of 2009, you have seen how important government spending can be for the economy. Government expenditure in the United States is about 20 percent of GDP and includes spending by all three levels of government: federal, state, and local. The only part of government spending counted in demand is government purchases of goods or services produced in the economy. Examples include the government buying a new fighter jet for the Air Force (federal government spending), building a new highway (state government spending), or setting up a new school (local government spending). A significant portion of government budgets are transfer payments, like unemployment benefits, veteran's benefits, and Social Security payments to retirees. These payments are excluded from GDP because the government does not receive a new good or service in return or exchange. Instead, they are transfers of income from taxpayers to others. If you are curious about the awesome undertaking of adding up GDP, read the following Clear It Up feature.

Clear It Up

How do statisticians measure GDP?

Government economists at the BEA, within the U.S. Department of Commerce, piece together estimates of GDP from a variety of sources.

Once every five years, in the second and seventh year of each decade, the Census Bureau carries out a detailed census of businesses throughout the United States. In between, it carries out a monthly survey of retail sales. These figures are adjusted with foreign trade data to account for exports that are produced in the United States and sold abroad and for imports that are produced abroad and sold here. Once every 10 years, the Census Bureau conducts a comprehensive survey of housing and residential finance. Together, these sources provide the main basis for figuring out what is produced for consumers.

For investment, the Census Bureau carries out a monthly survey of construction and an annual survey of expenditures on physical capital equipment.

For what is purchased by the federal government, the statisticians rely on the U.S. Department of the Treasury. An annual Census of Governments gathers information on state and local governments. Because a lot of government spending at all levels involves hiring people to provide services, a large portion of government spending is also tracked through payroll records collected by state governments and by the Social Security Administration.

With regard to foreign trade, the Census Bureau compiles a monthly record of all import and export documents. Additional surveys cover transportation and travel, and adjustment is made for financial services that are produced in the United States for foreign customers.

Many other sources contribute to the estimates of GDP. Information on energy comes from the U.S. Department of Transportation and Department of Energy. Information on healthcare is collected by the Agency for Healthcare Research and Quality. Surveys of landlords find out about rental income. The Department of Agriculture collects statistics on farming.

All of these bits and pieces of information arrive in different forms, at different time intervals. The BEA melds them to produce estimates of GDP on a quarterly basis (every three months). These numbers are then annualized by multiplying by four. As more information comes in, these estimates are updated and revised. The advance estimate of GDP for a certain quarter is released one month after a quarter. The preliminary estimate comes out one month after that. The final estimate is published one month later, but it is not actually final. In July, roughly updated estimates for the previous calendar year are released. Then, once every five years, after the results of the latest detailed five-year business census have been processed, the BEA revises all of the past estimates of GDP according to the newest methods and data, going all the way back to 1929.

Link It Up

Visit this website to read FAQs on the BEA site. You can even email your own questions!

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When thinking about the demand for domestically produced goods in a global economy, it is important to count spending on exports—domestically produced goods that are sold abroad. By the same token, we must also subtract spending on imports—goods produced in other countries that are purchased by residents of this country. The net export component of GDP is equal to the dollar value of exports (X) minus the dollar value of imports (M): (X – M). The gap between exports and imports is called the trade balance. If a country’s exports are larger than its imports, then a country is said to have a trade surplus. In the United States, exports typically exceeded imports in the 1960s and 1970s, as shown in Figure 5.4 (b).

Since the early 1980s, imports have typically exceeded exports, and so the United States has experienced a trade deficit in most years. Indeed, the trade deficit grew quite large in the late 1990s and in the mid-2000s. Figure 5.4 (b) also shows that imports and exports have both risen substantially in recent decades, even after the declines during the Great Recession between 2008 and 2009. As noted before, if exports and imports are equal, foreign trade has no effect on total GDP. However, even if exports and imports are balanced overall, foreign trade might still have powerful effects on particular industries and workers by causing nations to shift workers and physical capital investment toward one industry rather than another.

Based on these four components of demand, GDP can be measured as

GDP = Consumption + Investment + Government + Trade balanceGDP = C + I + G + (X – M).GDP = Consumption + Investment + Government + Trade balanceGDP = C + I + G + (X – M).

Understanding how to measure GDP is important for analyzing connections in the macroeconomy and for thinking about macroeconomic policy tools.

GDP Measured by What Is Produced

GDP Measured by What Is Produced

Everything that is purchased must be produced first. Table 5.2 breaks down what is produced into five categories: durable goods, nondurable goods, services, structures, and the change in inventories. Before going into detail about these categories, notice that total GDP measured according to what is produced is exactly the same as the GDP measured by looking at the five components of demand. Figure 5.5 provides a visual representation of this information.

Components of GDP on the Supply Side (in Trillions of Dollars) Percentage of Total
Durable goods $2.9 16.7%
Nondurable goods $2.3 13.2%
Services $10.8 62.1%
Structures $1.3 7.4%
Change in inventories $0.1 0.6%
Total GDP $17.4 100%
Table 5.2 Components of U.S. GDP on the Production Side, 2014 (Source: http://bea.gov/iTable/index_nipa.cfm)
The pie chart shows that services take up almost half of the chart, followed by durable goods, nondurable goods, structures, and change in inventories.
Figure 5.5 Percentage of Components of GDP on the Production Side Services make up over half of the production side components of GDP in the United States.

Since every market transaction must have both a buyer and a seller, GDP must be the same whether measured by what is demanded or by what is produced. Figure 5.6 shows the components of what is produced, expressed as a percentage of GDP, since 1960.

The graph shows that since 1960, structures have mostly remained around 10%, but dipped to 7.7% in 2014, and durable goods have mostly remained around 20%, but dipped in 2014 to 16.8%. The graph also shows that services have steadily increased from less than 30% in 1960 to over 61.9%  in 2014. In contrast, nondurable goods have steadily decreased from roughly 40% in 1960 to around 13.7% in 2014.
Figure 5.6 Types of Production Services are the largest single component of total supply, representing over half of GDP. Nondurable goods used to exceed durable goods, but, in recent years, nondurable goods have been dropping closer to durable goods, which make up about 20 percent of GDP. Structures hover around 10 percent of GDP. The change in inventories, which is the final component of aggregate supply, is not shown here; it is typically less than one percent of GDP.

In thinking about what is produced in the economy, many non-economists immediately focus on solid, long-lasting goods, like cars and computers. By far the largest part of GDP, however, is services. Moreover, services have been a growing share of GDP over time. A detailed breakdown of the leading service industries would include healthcare, education, and legal and financial services. It has been decades since most of the U.S. economy involved making solid objects. Instead, the most common jobs in a modern economy involve a worker looking at pieces of paper or a computer screen; meeting with co-workers, customers, or suppliers; or making phone calls.

Even within the overall category of goods, long-lasting durable goods like cars and refrigerators make up about the same share of the economy as short-lived nondurable goods like food and clothing. The category of structures includes everything from homes to office buildings, shopping malls, and factories. Inventories is a small category that refers to goods that have been produced by one business but have not yet been sold to consumers and are still sitting in warehouses and on shelves. The amount of inventories sitting on shelves tends to decline if business is better than expected, or to rise if business is worse than expected.

The Problem of Double Counting

The Problem of Double Counting

GDP is defined as the current value of all final goods and services produced in a nation in a year. What are final goods? They are goods at the furthest stage of production at the end of a year. Statisticians who calculate GDP must avoid the mistake of double counting, in which output is counted more than once as it travels through the stages of production. For example, imagine what would happen if government statisticians first counted the value of tires produced by a tire manufacturer, and then counted the value of a new truck sold by an automaker that contains those tires. In this example, the value of the tires would have been counted twice—because the price of the truck includes the value of the tires.

To avoid this problem, which would overstate the size of the economy considerably, government statisticians count just the value of final goods and services in the chain of production that are sold for consumption, investment, government, and trade purposes. Intermediate goods, which are goods that go into the production of other goods, are excluded from GDP calculations. From the example above, only the value of the Ford truck will be counted. The value of what businesses provide to other businesses is captured in the final products at the end of the production chain.

The concept of GDP is fairly straightforward: It is just the dollar value of all final goods and services produced in the economy in a year. However, in our decentralized, market-oriented economy, actually calculating the more than $16 trillion-dollar U.S. GDP—along with how it is changing every few months—is a full-time job for a brigade of government statisticians.

What is counted in GDP What is not included in GDP
Consumption Intermediate goods
Business investment Transfer payments and non-market activities
Government spending on goods and services Used goods
Net exports Illegal goods
Table 5.3 Counting GDP

Notice the items that are not counted in GDP, as outlined in Table 5.3. The sales of used goods are not included because they were produced in a previous year and are part of that year’s GDP. The entire underground economy of services paid “under the table and illegal sales should be counted, but is not, because it is impossible to track these sales. In a recent study by Friedrich Schneider (2013) of shadow economies, the underground economy in the United States was estimated to be 6.6 percent of GDP, or close to $2 trillion dollars, in 2013 alone. Transfer payments, such as payment by the government to individuals, are not included, because they do not represent production. Also, production of some goods—such as home production; e.g., when you make your breakfast—not counted because these goods are not sold in the marketplace.

Link It Up

Visit this website to read about the “New Underground Economy.”

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Other Ways to Measure the Economy

Other Ways to Measure the Economy

Besides GDP, there are several different but closely related ways of measuring the size of the economy. We mentioned above that GDP can be thought of as total production and as total purchases. It can also be thought of as total income, since anything produced and sold produces income.

One of the closest cousins of GDP is the gross national product (GNP). GDP includes only what is produced within a country’s borders. GNP adds what is produced by domestic businesses and labor abroad, and subtracts any payments sent home to other countries by foreign labor and businesses located in the United States. In other words, GNP is based more on the production of citizens and firms of a country, wherever they are located, and GDP is based on what happens within the geographic boundaries of a certain country. For the United States, the gap between GDP and GNP is relatively small; in recent years, only about 0.2 percent. For small nations, which may have a substantial share of their population working abroad and sending money back home, the difference can be substantial.

Net national product (NNP) is calculated by taking GNP and then subtracting the value of how much physical capital is worn out, or reduced in value because of aging, over the course of a year. The process by which capital ages and loses value is called depreciation. The NNP can be further subdivided into national income, which includes all income to businesses and individuals, and personal income, which includes only income to people.

For practical purposes, it is not vital to memorize these definitions. However, it is important to be aware that these differences exist and to know what statistic you are looking at so that you do not accidentally compare, say, GDP in one year or for one country with GNP or NNP in another year or another country. To get an idea of how these calculations work, follow the steps in the following Work It Out feature.

Work It Out

Calculating GDP, Net Exports, and NNP

Based on the information in Table 5.4

  1. What is the value of GDP?
  2. What is the value of net exports?
  3. What is the value of NNP?
Government purchases $120 billion
Depreciation $40 billion
Consumption $400 billion
Business investment $60 billion
Exports $100 billion
Imports $120 billion
Income receipts from rest of the world$10 billion
Income payments to rest of the world$8 billion
Table 5.4

Step 1. To calculate GDP, use the following formula

GDP = Consumption + Investment + Government spending + (Exports – Imports) = C + I + G + (X – M) = $400 + $60 + $120 + ($100 – $120) = $560 billion.GDP = Consumption + Investment + Government spending + (Exports – Imports) = C + I + G + (X – M) = $400 + $60 + $120 + ($100 – $120) = $560 billion.

Step 2. To calculate net exports, subtract imports from exports.

Net exports = X – M = $100 – $120 = –$20 billionNet exports = X – M = $100 – $120 = –$20 billion

Step 3. To calculate NNP, use the following formula

NNP = GDP + Income receipts from the rest of the world– Income payments to the rest of the world – Depreciation=$560 + $10 – $8 – $40=$522 billion.NNP = GDP + Income receipts from the rest of the world– Income payments to the rest of the world – Depreciation=$560 + $10 – $8 – $40=$522 billion.


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