12.1 Aggregate demand in keynesian analysis  (Page 3/13)

Many factors can affect the expected profitability on investment. For example, if the price of energy declines, then investments that use energy as an input will yield higher profits. If government offers special incentives for investment (for example, through the tax code), then investment will look more attractive; conversely, if government removes special investment incentives from the tax code, or increases other business taxes, then investment will look less attractive. As Keynes noted, business investment is the most variable of all the components of aggregate demand.

What determines government spending?

The third component of aggregate demand is spending by federal, state, and local governments. Although the United States is usually thought of as a market economy, government still plays a significant role in the economy. As we discuss in Environmental Protection and Negative Externalities and Positive Externalitites and Public Goods , government provides important public services such as national defense, transportation infrastructure, and education.

Keynes recognized that the government budget offered a powerful tool for influencing aggregate demand. Not only could AD be stimulated by more government spending (or reduced by less government spending), but consumption and investment spending could be influenced by lowering or raising tax rates. Indeed, Keynes concluded that during extreme times like deep recessions, only the government had the power and resources to move aggregate demand.

What determines net exports?

Recall that exports    are products produced domestically and sold abroad while imports    are products produced abroad but purchased domestically. Since aggregate demand is defined as spending on domestic goods and services, export expenditures add to AD, while import expenditures subtract from AD.

Two sets of factors can cause shifts in export and import demand: changes in relative growth rates between countries and changes in relative prices between countries. The level of demand for a nation’s exports tends to be most heavily affected by what is happening in the economies of the countries that would be purchasing those exports. For example, if major importers of American-made products like Canada, Japan, and Germany have recessions, exports of U.S. products to those countries are likely to decline. Conversely, the quantity of a nation’s imports is directly affected by the amount of income in the domestic economy: more income will bring a higher level of imports.

Exports and imports can also be affected by relative prices of goods in domestic and international markets. If U.S. goods are relatively cheaper compared with goods made in other places, perhaps because a group of U.S. producers has mastered certain productivity breakthroughs, then U.S. exports are likely to rise. If U.S. goods become relatively more expensive, perhaps because a change in the exchange rate between the U.S. dollar and other currencies has pushed up the price of inputs to production in the United States, then exports from U.S. producers are likely to decline.

[link] summarizes the reasons given here for changes in aggregate demand.

Key concepts and summary

Aggregate demand is the sum of four components: consumption, investment, government spending, and net exports. Consumption will change for a number of reasons, including movements in income, taxes, expectations about future income, and changes in wealth levels. Investment will change in response to its expected profitability, which in turn is shaped by expectations about future economic growth, the creation of new technologies, the price of key inputs, and tax incentives for investment. Investment will also change when interest rates rise or fall. Government spending and taxes are determined by political considerations. Exports and imports change according to relative growth rates and prices between two economies.

References

Mahapatra, Lisa. “US Exports To China Have Grown 294% Over The Past Decade.” International Business Times . Last modified July 09, 2013. http://www.ibtimes.com/us-exports-china-have-grown-294-over-past-decade-1338693.

The Conference Board, Inc. “Global Economic Outlook 2014, November 2013.” http://www.conference-board.org/data/globaloutlook.cfm.

Thomas, G. Scott. “Recession claimed 170,000 small businesses in two years.” The Business Journals . Last modified July 24, 2012. http://www.bizjournals.com/bizjournals/on-numbers/scott-thomas/2012/07/recession-claimed-170000-small.html.

United States Department of Labor: Bureau of Labor Statistics. “Top Picks.” http://data.bls.gov/cgi-bin/surveymost?bls.