Chapter 10: Investment and Economic Activity – Long-Run Growth, Savings, and Financial Markets

Investment and Economic Activity

Long-Run Economic Growth

Long-run economic growth refers to the sustained increase in a nation's productive capacity, which raises the average standard of living. This process is driven by rising productivity and is distinct from short-run fluctuations known as the business cycle, which includes periods of expansion and recession.

• Long-run economic growth: The process by which productivity increases over time, improving living standards.

• Business cycle: Alternating periods of economic expansion and recession.

• Real GDP per capita: The most common measure of average living standards, calculated as total production in the economy per person, adjusted for price changes.

• Example: The U.S. has experienced steady growth in real GDP per capita from 1980 to 2023, with notable dips during recessions.

Potential GDP

Potential GDP is the level of real GDP achieved when all firms are operating at normal capacity, defined by regular working hours and a typical workforce size. It represents the economy's maximum sustainable output.

• Potential GDP: The output level when resources are fully employed at normal rates.

• Potential GDP increases when the labor force grows, capital stock expands, or new technologies are introduced.

• In the U.S., potential GDP has grown at about 3.2% annually over recent decades.

• Example: The 2007-2009 recession caused a significant gap between actual and potential GDP.

Rule of 70

The Rule of 70 is a simple formula used to estimate the number of years required for a variable to double, given a constant growth rate.

• Formula: $\text{Doubling Time} = \frac{70}{\text{Growth Rate (in %)}}$

• Example:

  • 1% growth rate: 70 years to double

  • 2% growth rate: 35 years to double

  • 3% growth rate: 23.33 years to double

Financial Markets and Financial Intermediaries

Financial markets facilitate the buying and selling of financial securities, such as stocks and bonds. Financial intermediaries are institutions that channel funds from savers to borrowers.

• Financial security: A document stating the terms under which funds are transferred.

• Stock: Represents partial ownership in a firm.

• Bond: A promise to repay a fixed amount; essentially a loan from a household to a firm.

• Financial intermediaries: Banks, mutual funds, pension funds, and insurance companies that facilitate the flow of funds.

Three Key Services of the Financial System

The financial system provides essential services that support economic growth and investment.

• Risk sharing: Diversification allows investors to reduce risk while maintaining expected returns.

• Liquidity: Enables savers to quickly convert investments into cash.

• Information: Prices of securities reflect collective beliefs about future returns, guiding funds to productive uses.

Savings and Investment

Savings represent funds set aside in accounts, bonds, stocks, or certificates of deposit. Investment refers to funds borrowed for productive use, often in the form of loans.

• Savings: Money placed in financial instruments for future use.

• Investment: Money borrowed to finance capital projects.

• National income identity:

  • $Y = C + I + G$

  • $Y - C - G = I$

  Where: $Y$ = GDP, $C$ = Consumption, $I$ = Investment, $G$ = Government spending

Savings: Private and Public

Total savings in an economy consist of private savings (by households) and public savings (by the government).

• Private savings ($S_{private}$): Household income not spent, including payments for factors of production and transfer payments, minus consumption and taxes. $S_{private} = Y + TR - C - T$ Where $TR$ = Transfer payments, $T$ = Taxes

• Public savings ($S_{public}$): Government income minus spending and transfer payments. $S_{public} = T - G - TR$ Where $G$ = Government spending

• Total savings ($S$): $S = S_{private} + S_{public}$ $S = Y - C - G$

Apply the Concept: Ebenezer Scrooge and Economic Growth

In A Christmas Carol, Ebenezer Scrooge is depicted as a miser, but his decision to save rather than consume can promote economic growth. Savings are channeled into investment, increasing productive capacity and future consumption.

• By saving, resources are allocated to investment, which boosts long-term growth.

• Society may benefit more from increased investment than from immediate consumption.

• Example: Scrooge's savings could lead to stronger economic growth than his spending.

Market for Loanable Funds

The market for loanable funds determines the equilibrium interest rate and quantity of funds available for investment. Savings supply funds, while investment creates demand.

• Supply of loanable funds: Influenced by taxes, consumption, income, and government budget.

• Demand for loanable funds: Influenced by economic activity, input costs, natural disasters, and technology.

• Graph: The intersection of the supply and demand curves sets the equilibrium interest rate and quantity of loanable funds.

Why Invest and What In?

Investment is crucial for long-term economic growth, as it increases both physical and human capital.

• Physical capital: Machinery, buildings, and equipment that enhance productivity.

• Human capital: Education and skills that improve labor productivity.

• Production Possibilities Frontier (PPF): Investment shifts the PPF outward, indicating greater productive capacity.

Summary Table: Savings and Investment Equations

Type	Equation	Description
National Income Identity	$Y = C + I + G$	GDP equals consumption, investment, and government spending
Investment	$I = Y - C - G$	Investment equals GDP minus consumption and government spending
Private Savings	$S_{private} = Y + TR - C - T$	Household income not spent
Public Savings	$S_{public} = T - G - TR$	Government income minus spending and transfers
Total Savings	$S = S_{private} + S_{public}$	Sum of private and public savings

Additional info: The notes include a practical application of savings and investment through the example of Ebenezer Scrooge, and graphical representations of GDP growth and the market for loanable funds, which are standard topics in macroeconomics.