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MACROECONOMICS MACROECONOMICS

Topic 2

Macroeconomic data

(Chapter 2)

Instructor: Tuan Khai Vu

ICU, Winter Term 2011

Principles of Macroeconomics

Learning objectives

Learning objectives

In this chapter, you will learn about how

we define and measure:

• Gross Domestic Product (GDP)

• the Consumer Price Index (CPI)

• the Unemployment Rate

Why need to measure

• To know more precisely about the state of

the economy

• To draw quick and right policy responses

• To build and test theory

Æ Deeper understanding. Also recall that macro is a science.

• Measuring itself in economics

general,

is often challenging but interesting

and very much worth doing.

Gross Domestic Product

Gross Domestic Product

Two definitions of GDP:

1. Total expenditure on

domestically-produced

final goods and services

2. Total income earned by

domestically-located

factors of production

Why expenditure = income

Why expenditure = income

I n every transaction,

the buyer’s expenditure

becomes the seller’s income.

Thus, the sum of all

expenditure equals

the sum of all income.

I n every transaction,

I n every transaction,

the buyer

the buyer ’ _’ s expenditure s expenditure

becomes the seller

becomes the seller ’ _’ s income. _{s income.}

Thus, the sum of all

Thus, the sum of all

expenditure equals

expenditure equals

the sum of all income.

the sum of all income.

The Circular Flow

The Circular Flow

Income ($ ) Labor

Goods (bread ) Expenditure ($ )

Households Firms

Adding markets and government …

Final goods, value added, and GDP

• GDP = value of final goods produced

= sum of value added at all stages of production.

• Value added: The value of output minus the value of the intermediate goods used to

produce that output.

• The value of the final goods already includes the value of the intermediate goods, so

including intermediate and final goods in GDP would be double-counting.

The expenditure components of GDP

• consumption, C

• investment, I

• government spending, G

• net exports, NX

An important identity:

Y = C + I + G + NX aggregate

value of

Consumption (C)

– durable goods last a long time

e.g., cars, refrigerators, TVs – nondurable goods

last a short time

e.g., food, clothing, shoes – services

work done for consumers

Definition: The value of all goods and services bought by households.

Includes:

U.S. consumption, 2008

42.6 20.8 7.2 70.5%

6,069.6 2,965.1 1,023.2

$ 10,057.9

Services

Nondurables Durables

Consumption

% of GDP

$ billions

Investment (I)

• Spending on goods bought for future use

(i.e., capital goods)

• Includes:

– Business fixed investment

Spending on plant and equipment – Residential fixed investment

Spending by consumers and landlords on housing units

– Inventory investment

The change in the value of all firms’

U.S. Investment, 2008

–0.3 3.4 10.9 14.0%

–47.0 487.7 1,552.8

$1,993.5

Inventory Residential

Business fixed Investment

% of GDP

$ billions

Investment vs. Capital

Investment vs. Capital

• Capital is one of the factors of production.

At any given moment, the economy has a certain overall stock of capital.

• Investment is spending on new capital.

• Example (assumes no depreciation):

– 1/1/2009: economy has $500b worth of capital. – during 2009: investment = $60b.

– 1/1/2010: economy will have $560b worth of capital.

Stocks vs. Flows

A stock is a

quantity measured at a point in time. E.g.: Capital.

Flow ^Stock

A flow is a quantity measured per unit of time.

E.g.: Investment.

Stocks vs. Flows - more examples

the govt budget deficit the govt debt

# of new college graduates this year

# of people with college degrees

a person’s annual saving a person’s wealth

flow stock

Government spending (

Government spending ( G _G ) ₎

• G includes all government spending on

goods and services.

• G excludes transfer payments

(e.g. unemployment insurance payments),

because they do not represent spending

on goods and services.

U.S. Government Spending,

2008

- Federal

20.2%

$2,882.4 Govt spending

- State & local Defense

7.5

12.7 5.2 2.4 1,071.9

1,810.4 734.9 337.0 Non-defense

% of GDP

$ billions

Net Exports: NX = EX – IM

• def: the value of total exports (EX) minus the

value of total imports (IM)

Reconfirm the important identity

Reconfirm the important identity

Y = C + I + G + NX

aggregate expenditure value of

total output

A question:

Suppose a firm

• produces $10 million worth of final goods

• but only sells $9 million worth. Does this violate the

expenditure = output identity?

Why output = expenditure

Why output = expenditure

• Unsold output goes into inventory,

and is counted as “inventory

investment”…

…whether the inventory buildup was

intentional or not.

• In effect, we are assuming that

firms purchase their unsold output.

GDP:

GDP:

An important and versatile concept

An important and versatile concept

We have now seen that GDP measures

ƒ total income

ƒ total output

ƒ total expenditure

ƒ the sum of value-added at all stages in the production of final goods

GNP vs. GDP

• Gross National Product (GNP):

Total income earned by the nation’s factors of production, regardless of where located

• Gross Domestic Product (GDP):

Total income earned by domestically-located factors of production, regardless of nationality GNP – GDP = (factor payments from abroad)

– (factor payments to abroad)

• Examples of factor payments: wages, profits,

Discussion Question:

Discussion Question:

What explains why GNP

differs from GDP for some of

the following countries?

GNP vs. GDP in selected countries, 2007

Country GNP GDP ^{GNP – GDP}

(% of GDP)

Philippines $157,087 $144,062 9.0%

Japan $4,530,191 $4,384,255 3.3%

China $3,229,841 $3,205,507 0.8%

United States $13,827,201 $13,751,400 0.6% Canada $1,318,304 $1,329,885 –0.9% South Africa $274,141 $283,007 –3.1% New Zealand $125,936 $135,667 –7.2%

Real vs. Nominal GDP

Real vs. Nominal GDP

• GDP is the valueof all final goods and

services produced.

• Nominal GDP measures these values

using current prices.

• Real GDP measure these values using the

prices of a base year.

Real vs. nominal GDP

GDP

^{= P}

^Q

∑

RGDP

^{= P}

^Q

∑

The same year’s

(i.e. current) _price

Real GDP controls for inflation

Real GDP controls for inflation

Changes in nominal GDP can be due to:

ƒ changes in prices

ƒ changes in quantities of output produced

Changes in real GDP can only be due to

changes in quantities, because real GDP is

constructed using constant base-year prices.

Practice problem

Practice problem

2002 2003

P Q P Q

good A $1 10 $2 15

good B $10 3 $15 4

• Compute nominal GDP in 2002 and 2003

• Compute real GDP in each year using

Answers to practice problem

Answers to practice problem

• Nominal GDP multiply P & Q from same year

2002: $1 x 10 + $10 x 3 = $40 2003: $2 x 15 + $15 x 4 = $90

• Real GDP multiply each year’s Q by 2002 P

2002: as above: $40

2003: $1 x 15 + $10 x 4 = $55 (2002$)

• So in real terms, GDP did not rise as much as it would seem from nominal terms.

31

U.S. Nominal and Real GDP, 1960-2009

GDP Deflator

GDP Deflator

• The inflation rate is the percentage

increase in the overall level of prices.

• One measure of the price level is

the GDP Deflator, defined as

Nominal GDP GDP deflator = 100

Real GDP

×

Understanding the GDP deflator

Understanding the GDP deflator

Example with 3 goods

For good

_i

P_it = the market price of good

i

Q_it = the quantity of good

_i

NGDP_t = Nominal GDP in month t

RGDP_t = Real GDP in month t

Understanding the GDP deflator

Understanding the GDP deflator

t t

GDP deflator NGDP

= ¹⁰⁰ × RGDP ^{1t 1t 2t 2t 3t 3t}

t

P Q P Q P Q

RGDP

+ +

= ¹⁰⁰ ×

⎛ ⎞ ⎛ ⎞ ⎛ ⎞

⎜ ⎟ ⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠ ⎝ ⎠

⎡ ⎤

⎢ ⎥

= × _⎢ + + _⎥

⎢ ⎥

⎢ ⎥

⎣ ^{    } ⎦

1t 2t 3t

t t t

weight 1 weight 2 weight 3

1t 2t 3t

Q Q Q

RGDP ^P RGDP ^P RG PD ^P

100

The GDP deflator is a weighted average of prices. The weight on each price reflects

that good’s relative importance in GDP. Note that the weights ^{(Q/ RGDP)} change over time.

Working with percentage

Working with percentage

changes

changes

• A percentage change (or the rate of change)

of a variable X is defined as

= × −

 ^,

rate of change of X in %

(% ) ^t

X t

X X

g X

0 0

100

Working with percentage

Working with percentage

changes

changes

USEFUL TRI CK # 1 For any variables X and Y, the percentage change in (X _× Y )

≈ the percentage change in X

+ the percentage change in Y USEFUL TRI CK # 1

USEFUL TRI CK # 1 For any variables For any variables X_X ^and and ^YY^, , the percentage change in (

the percentage change in (X_{X ××}Y_Y))

≈≈ the percentage change in the percentage change in X_X

+ + the percentage change in the percentage change in Y_Y

EX: If your hourly wage rises 5%

and you work 7% more hours,

then your wage income rises approximately

12%.

Working with percentage

Working with percentage

changes

changes

USEFUL TRI CK # 2

the percentage change in (X/Y )

≈ the percentage change in X

− the percentage change in Y USEFUL TRI CK # 2

USEFUL TRI CK # 2

the percentage change in (

the percentage change in (X_X//Y_Y⁾)

≈≈ the percentage change in the percentage change in X_X

−− the percentage change in the percentage change in Y_Y

EX: GDP deflator = 100 _× NGDP/RGDP.

If NGDP rises 9% and RGDP rises 4%,

then the inflation rate is approximately 5%.

Consumer Price Index (CPI)

Consumer Price Index (CPI)

• A measure of the overall level of prices

• Published by the Bureau of Labor Statistics (BLS)

• Used to

– track changes in the

typical household’s cost of living – adjust many contracts for inflation

(i.e. “COLAs”)

– allow comparisons of dollar figures from different years

How the BLS constructs the CPI

How the BLS constructs the CPI

1. Survey consumers to determine composition of the typical consumer’s “basket” of goods.

2. Every month, collect data on prices of all items in the basket; compute cost of basket

3. CPI in any month equals

Cost of basket in that month 100 ^× Cost of basket in base period

The composition of the CPI

The composition of the CPI ’ _’ s _s

“ “ basket _basket ” _”

16.2%

40.0% 4.5%

17.6% ^{5.8% 5.9%}

2.8% 2.5% 4.8% Food and bev.

Housing Apparel

Transportation Medical care Recreation Education

Communication Other goods and services

Understanding the CPI

Understanding the CPI

Example with 3 goods

For good

_i

C_i = the amount of good

i

_i

E_t = the cost of the CPI basket in month t

E_b = cost of the basket in the base period

Understanding the CPI

Understanding the CPI

t b

CPI in month E

= ¹⁰⁰ × E

t ^{1t 1 2t 2 3t 3}

b

P C + P C + P C

= ¹⁰⁰ × E

N N N

⎡ ⎤

⎢ ⎥

= × _⎢^{⎛ ⎞}_{⎜ ⎟} + ^{⎛ ⎞}_{⎜ ⎟} + ^{⎛ ⎞}_{⎜ ⎟ ⎥}

⎝ ⎠ ⎝ ⎠ ⎝ ⎠

⎢ ⎥

⎢ ⎥

⎣ ⎦

3

1 2

b b b

weight 1 weight 2 weight 3

1t 2t 3t

P P ^C P

C C

E E E

100

The CPI is a weighted average of prices. The weight on each price reflects

that good’s relative importance in the CPI ’s basket. Note that the weights ^(C/Eb) remain fixed over time.

Reasons why

Reasons why

the CPI may overstate inflation

the CPI may overstate inflation

• Substitution bias: The CPI uses fixed weights, so it cannot reflect consumers’ ability to substitute toward goods whose relative prices have fallen.

• Introduction of new goods: The introduction of new goods makes consumers better off and, in

effect, increases the real value of the dollar. But it does not reduce the CPI, because the CPI uses fixed weights.

• Unmeasured changes in quality:

The CPI

The CPI ’ _’ s bias _{s bias}

• The Boskin Panel’s “best estimate”:

The CPI overstates the true increase in the

cost of living by 1.1% per year.

• Result: the BLS has refined the way it

calculates the CPI to reduce the bias.

• It is now believed that the CPI’s bias is

slightly less than 1% per year.

CPI vs. GDP deflator

CPI vs. GDP deflator

prices of capital goods

•

included in GDP deflator

•

excluded from CPI

prices of imported consumer goods

•

included in CPI

•

excluded from GDP deflator

the basket of goods

Two measures of inflation

Two measures of inflation

16 14 12 10 8 6 4 2 0 - 2 Percentage change

1948 1953 1958 1963 1968 1973 1978 1983 1988 1993 1998

CPI

GDP deflator

Measuring Unemployment:

Measuring Unemployment:

Categories of the population

Categories of the population

• employed

working at a paid job

• unemployed

not employed but looking for a job

• labor force

the amount of labor available for producing

goods and services; all employed plus

unemployed persons

• not in the labor force

Measuring Unemployment:

Measuring Unemployment:

Categories of the population

Categories of the population

• Graphically...

Population (i)

Out of the labor force

The labor

force ⁽ⁱⁱ⁾

Employed Unemployed

Two important labor force

Two important labor force

concepts

concepts

• unemployment rate

percentage of the labor force that is

unemployed

• labor force participation rate

the fraction of the adult population that

‘participates’ in the labor force

= (iii) / (ii)

= (ii) / (i)

Okun Okun ’ _’ s _s Law (Observation) Law (Observation)

• Employed workers help produce GDP,

while unemployed workers do not.

So one would expect

a negative relationship between

unemployment and real GDP.

• This relationship is clear in the data…

Okun Okun ’ _’ s _s Law _Law

1951 1984

1999 2000

1993

1982

1975 10

-3 _{-2 -1} 0 1 2 3 4

8 6 4 2 0 -2

Percentage change in real GDP

Okun’s Law states that a one-percent decrease in

unemployment is associated with two percentage points of additional growth in real GDP

Okun’s Law states that a one-percent decrease in

unemployment is associated with two percentage points of additional growth in real GDP

Chapter Summary

Chapter Summary

1. Gross Domestic Product (GDP) measures both total income and total expenditure on the economy’s output of goods & services. 2. Nominal GDP values output at current

prices; real GDP values output at constant prices. Changes in output affect both

measures, but changes in prices only affect nominal GDP.

3. GDP is the sum of consumption, investment, government purchases, and net exports.

Chapter Summary

Chapter Summary

4. The overall level of prices can be measured by either

ƒ the Consumer Price Index (CPI), the price of a fixed basket of goods purchased by the typical consumer

ƒ the GDP deflator,

the ratio of nominal to real GDP

5. The unemployment rate is the fraction of the labor force that is not employed.

When unemployment rises, the growth

54

Let’ s practice !

NOW YOU TRY:

Identifying value-added

• A farmer grows a bushel of wheat

and sells it to a miller for $1.00.

• The miller turns the wheat into flour

and sells it to a baker for $3.00.

• The baker uses the flour to make a loaf of

bread and sells it to an engineer for $6.00.

• The engineer eats the bread.

Compute value added at each stage

NOW YOU TRY:

Stock or Flow?

• the balance on your credit card statement

• how much you study economics outside of

class

• the size of your compact disc collection

• the inflation rate

• the unemployment rate

NOW YOU TRY:

Real & Nominal GDP

ƒ

ƒ

2006 2007 2008

P Q P Q P Q

good A $30 900 $31 1,000 $36 1,050 good B $100 192 $102 200 $100 205

NOW YOU TRY:

GDP deflator and inflation rate

ƒ

ƒ

Nom.

GDP ^{Real GDP}

GDP deflator

Inflation rate

2006 $46,200 $46,200 n.a.

2007 51,400 50,000 2008 58,300 52,000

NOW YOU TRY:

Computing labor statistics

U.S. adult population by group, May 2009

Number employed = 140.57 million Number unemployed = 14.51 million Adult population = 235.45 million

Use the above data to calculate

ƒ

ƒ

ƒ

NOW YOU TRY:

Compute percentage changes in

labor statistics

Suppose

ƒpopulation increases by 1%

ƒlabor force increases by 3%

ƒnumber of unemployed persons increases by 2%

Compute the percentage changes in the labor force participation and unemployment rates.