econ project
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The Standard of Living over Time and Across Countries
Describe the aggregate production function.
Explain how real GDP is determined in the long run.
Understand why the standard of living varies across countries.
Understand why labor productivity varies across countries.
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| Learning Objectives | |
| After studying this chapter, you should be able to: | |
| 5.1 | |
| 5.2 | |
| 5.3 | |
| 5.4 |
5
Who’s number one?
What is the leading economy in the world today?
The table shows two measures, with different results.
Both measures have some value.
Second table shows a wide disparity in standard of living between countries with highest GDP.
What explains differences, and changes, in standards of living?
| Rank | GDP | GDP per capita |
| 1 | United States | Qatar |
| 2 | China | Singapore |
| 3 | India | Norway |
| 4 | Japan | Hong Kong |
| 5 | Germany | United Arab Emirates |
| 6 | Russia | United States |
| 7 | Brazil | Switzerland |
| 8 | United Kingdom | Netherlands |
| 9 | France | Austria |
| 10 | Italy | Australia |
| Country | GDP | GDP per capita |
| United States | $15.0 trillion | $48,100 |
| China | 11.3 trillion | 8,400 |
| India | 4.5 trillion | 3,700 |
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Some countries have experienced rapid rates of long-run economic growth, while other countries have grown slowly, if at all.
Why isn’t the whole world rich?
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Key Issue and Question
Issue:
Question:
Describe the aggregate production function.
5.1
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| Learning Objective |
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The aggregate production function
Firms combine land, labor, natural resources, and capital to produce goods and services.
Technology represents the processes used to turn inputs into outputs.
Can include new products.
Improved management and/or worker skills.
Improved speed and efficiency in production.
A production function is a microeconomic concept applied to a firm that can be expanded to the macroeconomic level.
Aggregate production function An equation that shows the relationship between the inputs employed by firms and the maximum output firms can produce with those inputs.
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General aggregate production function
At the macroeconomic level, output is measured as real GDP (Y).
Include only labor and capital as inputs.
Y = real GDP, K = capital stock, L = labor, A = index of technology
Y = A × F(K,L), or Y = AF(K,L)
The higher the value of A, the more efficient is the economy and the higher is real GDP.
“A” measures the influence of all factors of production other than labor or capital used in production.
Factors that can affect the value of A:
Technology
Government regulations and institutions
Quality of the labor force
Geography
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Land/natural resources incorporated into A; changes relatively unimportant for a given economy.
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The Cobb-Douglas production function
Cobb-Douglas production function A widely-used macroeconomic production function that takes the form Y = AKαL1-α.
Notice that the sum of the exponents on capital and labor is 1.
Suppose α = 1/3, so that 1 – α = 2/3. Then we would write:
Y = AK1/3L2/3
Suppose A = 1,627; K = $40,000 billion; and L = 140 million workers. Then
Y = 1,627 ×($40,000 billion)1/3 × (0.140 billion workers)2/3
= $15.002 billion
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Properties of Cobb-Douglas production function
Cobb-Douglas production function is just one possible production function we could use to model output.
But it is commonly used, because it is simple, and seems to do a good job of explaining changes in GDP over time within a country.
Cobb-Douglas production function has several important properties:
The function exhibits constant returns to scale.
The function exhibits diminishing returns.
Capital and labor both earn shares of total income equal to the value of their exponents in the production function.
Next slides will discuss 1. and 2.; 3. left until later.
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Constant returns to scale
Constant returns to scale A property of a production function such that if all inputs increase by the same percentage, real GDP increases by the same percentage.
Under constant returns to scale, if the quantities of capital and labor both double, real GDP will also double:
2Y = AF(2K,2L)
The Cobb-Douglas production function has constant returns to scale, because the exponents (α and 1-α) add up to 1.
Example: Multiplying both capital and labor by 5, we obtain:
Y = A(5K)1/3(5L)2/3 = 5(1/3+2/3)AK1/3L2/3 = 5AK1/3L2/3
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A microeconomic example might help here; like “suppose a pizza parlor uses 20 workers and 2 pizza ovens to produce 200 pizzas per day. If the owner of pizza parlor expands her business to using 40 workers and 4 pizza ovens and her production function has constant returns to scale, she will now be able to produce 400 pizzas.”
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Diminishing marginal returns
Diminishing marginal returns refers to the idea of the effect of increasing one factor being smaller for greater levels of that factor, keeping the other factors constant.
We can look at the marginal returns to capital and labor by considering the marginal product of capital and the marginal product of labor.
Marginal product of capital (MPK) The extra output a firm receives from adding one more unit of capital, holding all other inputs and efficiency constant.
Marginal product of labor (MPL) The extra output a firm receives from adding one more unit of labor, holding all other inputs and efficiency constant.
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Diminishing marginal returns to capital
This panel shows the aggregate production function, holding labor and efficiency constant.
It allows us to show the marginal product of capital:
As we increase capital (moving along the K axis), MPK is falling: diminishing marginal returns to capital.
Aggregate production functions
Figure 5.1a
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Diminishing marginal returns to labor
This panel shows the aggregate production function, holding capital and efficiency constant.
It allows us to show the marginal product of labor:
As we increase capital (moving along the L axis), MPL is falling: diminishing marginal returns to labor.
Aggregate production functions
Figure 5.1b
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Why diminishing marginal returns?
Diminishing marginal returns are easiest to understand in a microeconomic context.
Suppose you have two administrative assistants creating an accounting report, but they have only one computer.
Adding a second computer increases output a lot.
Adding a third computer increases output much less.
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The demand for labor and the demand for capital
Graphing MPK and MPL, we have:
Downward sloping MPK and MPL curves (diminishing marginal returns)
Both are always positive
The MPK and MPL curves are the demand curves for capital and labor respectively.
Hire capital or labor until price equals marginal productivity.
The marginal product of capital and marginal product of labor curves
Figure 5.2
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Changes in capital or labor
As we increase labor or capital, diminishing marginal returns means that the same increases in labor or capital will produce progressively smaller increases in real GDP.
The figure shows this for increases in labor.
The effect of an increase in labor in the aggregate production function
Figure 5.3a
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Changes in total factor productivity
The A in the Cobb-Douglas production function is also called total factor productivity (TFP).
Total factor productivity An index of the overall level of efficiency of transforming capital and labor into real GDP.
TFP does not experience diminishing marginal returns.
The effect of an increase in productivity in the aggregate production function
Figure 5.3b
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Foreign direct investment and real GDP in China
Foreign direct investment (FDI) refers to the purchase or building of capital goods by foreign firms.
2011: FDI in China = $116 billion
FDI in China increases Chinese stock of capital goods
Causes movement along production function
Also causes technology transfer: increase in TFP for China
U.S. companies reconsidering investing in China:
FDI in China largely from other Asian countries; 25% decrease from U.S.
Why? Partly sluggish growth in U.S.
Also Chinese government restrictions on FDI, and poor intellectual property controls
FDI from U.S. companies has been good for Chinese real GDP growth; but continued growth may require forward-thinking government policy.
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Making the Connection
Summary of an aggregate production graph
Summary of aggregate production function graph with capital on horizontal axis
Table 5.1
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Results would be similar with labor on horizontal axis
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Explain how real GDP is determined in the long run.
5.2
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| Learning Objective |
5
A model of real GDP in the long run
To examine aggregate real GDP, we first explain how firms choose quantities of capital and labor to maximize profit. Economists assume firms are profit maximizers, such that:
Firms purchase capital and hire labor only to maximize profits.
Firms operate in a perfectly competitive market (i.e., firms are price takers).
Firms take the price of capital and labor inputs as given.
Firms decide how much capital and labor to hire using available technology based on prices of output and inputs.
We consider the behavior of a single representative firm, and assume all firms act in a similar way.
Profit = Revenue – Cost
Profit = PY – (WL + RK)
Profit = PY – WL – RK
Profit Total revenue minus total cost.
Note: P = Nominal output price W = Nominal wage R = Nominal rental cost of capital
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The market demand for capital
Firms are price takers in input markets and will hire more capital as long as the revenue produced from the next unit of capital exceeds the rental rate.
Δ Profit = P ×MPK – R
So hire capital if
P ×MPK > R
Firms continue to hire until
MPK = R/P
= r
= real rental cost of capital
So the marginal product of capital curve is the demand curve for capital.
Aggregate capital and labor markets
Figure 5.4a
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Note standard assumption that the supply of capital is fixed (in short run)
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The market demand for labor
Since firms are price takers in input markets, firms will hire more workers as long as the revenue produced from the next worker exceeds the wage.
Δ Profit = P ×MPL – W
So hire workers if
P ×MPL > W
Firms continue to hire until
MPL = W/P
= w
= real wage
So the marginal product of labor curve is the demand curve for labor.
Aggregate capital and labor markets
Figure 5.4b
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Note standard assumption that the supply of labor is fixed (in short run)
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Combining the factor markets with aggregate production
Factor markets determine equilibrium prices and quantities of capital and labor.
In this panel, real GDP is determined with capital stock on the horizontal axis.
The lower graph shows how the equilibrium quantity of capital is determined.
The upper graph uses the production function and the level of capital to determine the level of real GDP.
Determination of real GDP
Figure 5.5a
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Combining the factor markets with aggregate production
Factor markets determine equilibrium prices and quantities of capital and labor.
In this panel, real GDP is determined with the quantity of labor on the horizontal axis.
The lower graph shows how the equilibrium quantity of labor is determined.
The upper graph uses the production function and the level of labor to determine the level of real GDP.
Determination of real GDP
Figure 5.5b
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The division of total income
What determined how much of total income is received by labor, and how much is received by capital?
Labor:
By definition, Total labor income = w ×L
But w = MPL; so Total labor income = MPL ×L
Assuming Cobb-Douglas production, we can derive that MPL = (1-α)(Y/L); so
Total labor income = (1-α)(Y/L) ×L
Labor’s share of total income = (1-α)Y
Capital:
By definition, Total capital income = r ×K
But r = MPK; so Total capital income = MPK ×K
Assuming Cobb-Douglas production, we can derive that MPK = α(Y/K); so
Total capital income = α(Y/K) ×K
Capital’s share of total income = αY
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The division of total income
What determined how much of total income is received by labor, and how much is received by capital?
Labor’s share of total income = (1-α)Y
Capital’s share of total income = αY
This result implies that over time, the shares of labor and capital in total income should be roughly constant.
Over time, in the U.S. and other high-income countries, labor’s share of total income has typically been about two-thirds, and capital’s share has been about one-third.
This fact gives some justification for using the Cobb-Douglas production function, since it generates this property.
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Calculating MPL and MPK
Suppose that the production function for the economy is:
Y = AK1/2L1/2
Assume that real GDP is $12,000 billion, capital stock is $40,000 billion, and the labor supply is 0.150 billion workers.
Calculate the value of the marginal product of capital. Given this value, if the capital stock increases by $1 billion, by how much will real GDP increase?
Calculate the value for the marginal product of labor. Given this value, if the labor supply increases by one worker, by how much will real GDP increase?
What fraction of total income is received by labor, and what fraction is received by capital?
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Solved Problem
Calculating MPL and MPK
Step 1 Review the chapter material.
Step 2 Answer part (a) by calculating the value of the marginal product of capital, and use the value to determine how much real GDP will increase if the capital stock increases by $1 billion.
The marginal product of capital is equal to the exponent on the capital term, multiplied by (Y/K):
MPK = ½ ($12,000 billion / $40,000 billion)
= $0.15 per dollar of capital
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Solved Problem
Calculating MPL and MPK
Step 3 Answer part (b) by calculating the value of the marginal product of labor and use the value to determine how much real GDP will increase if the labor supply increases by one hour.
The marginal product of labor is equal to the exponent on the labor term, multiplied by (Y/L):
MPL = ½ ($12,000 billion / 0.150 billion workers)
= $40,000 per worker
Step 4 Answer part (c) by determining labor and capital’s shares of total income.
In a Cobb-Douglas production function, the shares of labor and capital in total income both equal the value of their exponents.
So labor and capital each obtain ½ of total income.
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Solved Problem
What determines levels of real GDP across countries?
Countries such as the U.S., China, and India have high levels of real GDP.
Possible reasons:
Large quantities of capital and labor
High levels of total factor productivity
These three countries have the world’s three largest labor forces.
But of these three, only the U.S. has a high level of real GDP per capita. Why?
Labor productivity is the critical determinant of real GDP per capita
Labor productivity is much higher in the U.S. than in China or India
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Understand why the standard of living varies across countries.
5.3
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| Learning Objective |
5
The per worker production function
To explain labor productivity, we modify the Cobb-Douglas production function to the per worker production function, by multiplying each input by a factor of (1/L).
Because of constant returns to scale, real GDP is also multiplied by (1/L)
Y = AF(K,L)
Y (1/L) = AF(K (1/L), L (1/L))
Y/L = AF(K/L,1)
y = Af(k)
y is “output per worker”, or labor productivity.
k is the capital-labor ratio, K/L.
f(k) = F(k,1) is a convenient way to rewrite the function F.
Capital-labor ratio The dollar value of capital goods per unit of labor; measured as the dollar value of capital divided by the total number of workers.
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The per worker production function
The per worker production function is very similar to the production function we used earlier except that the capital–labor ratio is on the horizontal axis, and real GDP per worker is on the vertical axis.
Diminishing marginal returns are demonstrated by the flattening slope.
The per worker production function
Figure 5.6
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What determines labor productivity?
Per worker production function: y = Af(k)
Which is more important, the capital-labor ratio or total factor productivity?
Capital experiences diminishing returns, but total factor productivity does not; so generally, total factor productivity matters more for labor productivity.
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What determines real GDP per capita?
Labor productivity measure how much output, or real GDP, the economy can produce per worker:
Standard of living can be measured by real GDP per capita:
So both labor productivity and the fraction of the population working affect real GDP per capita.
Labor productivity is more important, because labor input cannot change very much.
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Capital allocation across countries
How well do international capital markets allocate capital?
If there are no barriers to capital mobility, and capital markets are functioning well, then capital should move to countries with the highest rates of return.
This should make rate of return to capital in each country equal.
The graph shows MPK varies relatively little, and is mostly unrelated to real GDP per worker.
Estimate: reallocating capital from low- to high-rate of return countries would increase real GDP per worker by only 0.1%.
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Macro Data
Understand why labor productivity varies across countries.
5.4
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| Learning Objective |
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What explains total factor productivity?
Capital accumulation experiences diminishing marginal returns, so increases in labor productivity generally come from total factor productivity.
Research and development, and the level of technology
Development of computers, assembly line technology, etc. has raised productivity of workers
Investment in R&D critical
In 2011, U.S. spent about $405 billion on R&D, more than either China or India
Quality of labor
Human capital improvements make workers more productive.
Average years of education for adults in U.S.: 13.3 years; China: 7.5 years; India: 4.4 years
Learning by doing is also critical.
Human capital The accumulated knowledge and skills that workers acquire from education and training or from life experiences.
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What explains total factor productivity?
Government and social institutions
Markets, secure property rights, and effective legal systems are critical for making workers more productive
Example: 20th century experience of North Korea (communist dictatorship, no strong markets, insecure property rights) vs. South Korea
South Korean real GDP per capita estimated at 17 times greater than in North Korea
Geography
Navigable rivers and coastline facilitate trade
Tropical climates experience higher rates of infectious disease such as malaria, reducing labor productivity
Agricultural productivity also important
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What explains total factor productivity?
The financial system
Well-functioning financial systems:
Households and firms can obtain capital
R&D investments are more likely
Capital flows to its most profitable use
Stock market liquidity also matters for economic growth
Investors are more likely to purchase stocks that they know will be easy to sell
This raises stock prices (value of firms)
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R&D spending and labor productivity
Why is labor productivity higher in the U.S. than in China?
One reason is the difference in research and development spending:
2.7% of GDP in U.S. vs. 1.6% in China
As recently as 1996, Chinese R&D spending: just 0.6% of GDP
Why can’t the Chinese government encourage more R&D spending?
Chinese economic freedom still low (138th out of 179 countries in 2012)
So Chinese firms still have little incentive to invest
Foreign firms investing in China are also constrained by government
Much land still collectively owned, reducing incentives to invest
While China has made remarkable progress in economic liberalization since the 1970s, investment in R&D is still low, hindering labor productivity growth.
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Making the Connection
How important were Chinese reforms of 1978
Republic of China established in 1911, ending hereditary rule.
But Republic of China had difficulty extending authority over country
People’s Republic of China established in 1949 created socialist economy based on state ownership.
Without secure property rights, markets limited and unimportant
In 1978, Deng Xiaoping began many economic reforms:
Allowed private ownership of farms and businesses
Allowed some crops to be sold in markets
Established special economic zones for foreign/domestic joint ventures
Opened country to international trade and finance
Reforms have allowed total factor productivity and real GDP per capita to increase rapidly in China. But continued improvement relies on continued commitment by Chinese government to economic liberalization.
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Making the Connection
Answering the key question
“Why isn’t the whole world rich?”
Countries with a low standard of living have low levels of total factor productivity, due to a combination of:
Lack of investment in R&D
Low quality of labor from low investment in education
Government institutions that do not protect private property and that discourage investment
Geography that makes trade difficult or makes diseases more prevalent
Lack of financial institutions that allow funds to flow to firms with profitable investment projects
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