© 2007 Thomson South-Western. Last Chapter … In the last chapter, we looked at how economists use GDP to measure the quantity of goods and services that

© 2007 Thomson South-Western


Last Chapter…• In the last chapter, we looked at how

economists use GDP to measure the quantity of goods and services that the economy is producing.

• To review…– What things are factored into the GDP?– What are the two kinds of GDP and what is the

difference?


This Chapter…• This chapter examines how economists

measure the overall cost of living and how today’s salaries compare to those of the past.

• To do this, we need to talk about something called the CPI or Consumer Price Index.

• Also factored in is something else called Inflation.


Measuring the Cost of Living• Inflation refers to a situation in which the

economy’s overall price level is rising.

• The inflation rate is the percentage change in the price level from the previous period.


THE CONSUMER PRICE INDEX• The consumer price index (CPI) is a measure

of the overall cost of the goods and services bought by a typical consumer.

• The US Bureau of Labor Statistics reports the CPI each month.

• It is used to monitor changes in the cost of living over time.


THE CONSUMER PRICE INDEX

When the CPI rises, the typical family has to spend more dollars to maintain the same standard of living.


How the Consumer Price Index Is Calculated

1. Fix the basket. Determine what prices are most important to the typical consumer.• The Bureau of Labor Statistics (BLS) identifies a

market basket of goods and services the typical consumer buys.

•The BLS conducts monthly consumer surveys to set the weights for the prices of those goods and services.



2. Find the prices. Find the prices of each of the goods and services in the basket for each point in time.

3. Compute the basket’s cost. Use the data on prices to calculate the cost of the basket of goods and services at different times.



4. Choose a base year and compute the index. • Designate one year as the base year, making it the

benchmark against which other years are compared. • Compute the index by dividing the price of the

basket in one year by the price in the base year and multiplying by 100.

100year basein basket of Price

services and goods ofbasket of Priceindex priceConsumer



5. Compute the inflation rate. The inflation rate is the percentage change in the price index from the preceding period.



• The inflation rate is calculated as follows:

CPI in Year 2 CPI in Year 1Inflation Rate in Year 2= 100

CPI in Year 1


MEASURING THE COST OF LIVING 12

EXAMPLE basket: {4 pizzas, 10 lattes}

$12 x 4 + $3 x 10 = $78

$11 x 4 + $2.5 x 10 = $69

$10 x 4 + $2 x 10 = $60

cost of basket

$3.00

$2.50

$2.00

price of latte

$122009

$112008

$102007

price of pizza

year

Compute CPI in each year

2007: 100 x ($60/$60) = 100

2008: 100 x ($69/$60) = 115

2009: 100 x ($78/$60) = 130

Inflation rate:

15%115 – 100

100x 100%=

13%130 – 115

115x 100%=

using 2007 base year:


A C T I V E L E A R N I N G A C T I V E L E A R N I N G 11

Calculate the CPICalculate the CPI

13

CPI basket: {10 lbs beef, 20 lbs chicken}

The CPI basket cost $120 in 2004, the base year.

A. Compute the CPI in 2005.

B. What was the CPI inflation rate from 2005-2006?

price of beef

price of chicken

2004 $4 $4

2005 $5 $5

2006 $9 $6



AnswersAnswers

14

A. Compute the CPI in 2005:

Cost of CPI basket in 2005= ($5 x 10) + ($5 x 20) = $150

CPI in 2005 = 100 x ($150/$120) = 125



price of beef

price of chicken

2004 $4 $4

2005 $5 $5

2006 $9 $6



AnswersAnswers

15

price of beef

price of chicken

2004 $4 $4

2005 $5 $5

2006 $9 $6



B. What was the inflation rate from 2005-2006?

Cost of CPI basket in 2006= ($9 x 10) + ($6 x 20) = $210

CPI in 2006 = 100 x ($210/$120) = 175

CPI inflation rate = (175 – 125)/125 = 40%



What’s in the CPI’s Basket?

43%

17%

15%

6%

6%

6%4% 3% Housing

Transportation

Food & Beverages

Medical care

Recreation

Education andcommunicationApparel

Other


CPI basket: {10# beef, 20# chicken}

2004-5: Households bought CPI basket.

2006: Households bought {5 lbs beef, 25 lbs chicken}.


Substitution biasSubstitution bias

17

beef chickencost of CPI

basket

2004 $4 $4 $120

2005 $5 $5 $150

2006 $9 $6 $210

A. Compute cost of the 2006 household basket.

B. Compute % increase in cost of household basket over 2005-6, compare to CPI inflation rate.



AnswersAnswers

18

A. Compute cost of the 2006 household basket.

($9 x 5) + ($6 x 25) = $195


Household basket in 2006: {5# beef, 25# chicken}


basket

2004 $4 $4 $120

2005 $5 $5 $150

2006 $9 $6 $210



AnswersAnswers

19

B. Compute % increase in cost of household basket over 2005-6, compare to CPI inflation rate.

Rate of increase: ($195 – $150)/$150 = 30%

CPI inflation rate from previous problem = 40%


Household basket in 2006: {5# beef, 25# chicken}


basket

2004 $4 $4 $120

2005 $5 $5 $150

2006 $9 $6 $210



Problems with the CPI: Substitution Bias

• Over time, some prices rise faster than others.

• Consumers substitute toward goods that become relatively cheaper.

• The CPI misses this substitution because it uses a fixed basket of goods.

• Thus, the CPI overstates increases in the cost of living.



Problems with the CPI: Introduction of New Goods

• The introduction of new goods increases variety, allows consumers to find products that more closely meet their needs.

• In effect, dollars become more valuable.

• The CPI misses this effect because it uses a fixed basket of goods.




Problems with the CPI: Unmeasured Quality Change

• Improvements in the quality of goods in the basket increase the value of each dollar.

• The BLS tries to account for quality changes but probably misses some, as quality is hard to measure.



Problems in Measuring the Cost of Living

• The substitution bias, introduction of new goods, and unmeasured quality changes cause the CPI to overstate the true cost of living.

• The issue is important because many government programs use the CPI to adjust for changes in the overall level of prices.

• The CPI overstates inflation by about 1 percentage point per year.


The GDP Deflator versus the Consumer Price Index

• What was the GDP deflator?

• The GDP deflator is calculated as follows:

G D P d efla to r =N o m in a l G D P

R eal G D P 1 0 0



• The BLS calculates other prices indexes:

• The index for different regions within the country.

• The producer price index, which measures the cost of a basket of goods and services bought by firms rather than consumers.



• Economists and policymakers monitor both the GDP deflator and the consumer price index to gauge how quickly prices are rising.

• There are two important differences between the indexes that can cause them to diverge.



• The GDP deflator reflects the prices of all goods and services produced domestically, whereas...

• …the consumer price index reflects the prices of all goods and services bought by consumers.



• The consumer price index compares the price of a fixed basket of goods and services to the price of the basket in the base year (only occasionally does the BLS change the basket)...

• …whereas the GDP deflator compares the price of currently produced goods and services to the price of the same goods and services in the base year.


Figure 2 Two Measures of Inflation

1965

Percentper Year

15

CPI

GDP deflator

10

5

01970 1975 1980 1985 1990 20001995 2005

© 2007 Thomson South-WesternMEASURING THE COST OF LIVING 30

Imported consumer goods:– included in CPI – excluded from GDP deflator

Imported consumer goods:– included in CPI – excluded from GDP deflator

The basket: CPI uses fixed basket GDP deflator uses basket of

currently produced goods & servicesThis matters if different prices are changing by different amounts.

The basket: CPI uses fixed basket GDP deflator uses basket of

currently produced goods & servicesThis matters if different prices are changing by different amounts.

Capital goods: excluded from CPI included in GDP deflator

(if produced domestically)

Capital goods: excluded from CPI included in GDP deflator

(if produced domestically)

Contrasting the CPI and GDP Deflator


In each scenario, determine the effects on the CPI and the GDP deflator.

A. Starbucks raises the price of Frappuccinos.

B. Caterpillar raises the price of the industrial tractors it manufactures at its Illinois factory.

C. Armani raises the price of the Italian jeans it sells in the U.S.


CPI vs. GDP deflatorCPI vs. GDP deflator

31


A. Starbucks raises the price of Frappuccinos.

The CPI and GDP deflator both rise.

B. Caterpillar raises the price of the industrial tractors it manufactures at its Illinois factory.

The GDP deflator rises, the CPI does not.

C. Armani raises the price of the Italian jeans it sells in the U.S.

The CPI rises, the GDP deflator does not.


AnswersAnswers

32


Correcting Variables for Inflation:Comparing Dollar Figures from Different Times

• Inflation makes it harder to compare dollar amounts from different times.

• Example: the minimum wage

– $1.15 in Dec 1964

– $5.85 in Dec 2007

• Did min wage have more purchasing power in Dec 1964 or Dec 2007?

• To compare, use CPI to convert 1964 figure into “today’s dollars”…


• In our example,

– year T = 12/1964, “today” = 12/2007

– Min wage = $1.15 in year T

– CPI = 31.3 in year T, CPI = 211.7 today


Amount in today’s

dollars

Amount in year T dollars

Price level today

Price level in year T= x

$7.78 $1.15211.731.3

= xThe minimum wage in 1964 was $7.78

in today’s (2007) dollars.



• Researchers, business analysts and policymakers often use this technique to convert a time series of current-dollar (nominal) figures into constant-dollar (real) figures.

• They can then see how a variable has changed over time after correcting for inflation.

• Example: the minimum wage, from Jan 1950 to Dec 2007…


The U.S. Minimum Wage in Current Dollarsand Today’s Dollars, 1950-2007

$ pe

r ho

ur

$0

$1

$2

$3

$4

$5

$6

$7

$8

$9

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

current dollars

2007 dollars


Annual tuition and fees, average of all public four-year colleges & universities in the U.S.

– 1986-87: $1,414 (1986 CPI = 109.6)

– 2006-07: $5,834 (2006 CPI = 203.8)

After adjusting for inflation, did students pay more for college in 1986 or in 2006? Convert the 1986 figure to 2006 dollars and compare.


Converting to “today’s dollars”Converting to “today’s dollars”

37



AnswersAnswers

38

Solution

Convert 1986 figure into “today’s dollars”

$1,414 x (203.8/109.6) = $2,629

Even after correcting for inflation, tuition and fees were much lower in 1986 than in 2006!

Annual tuition and fees, average of all public four-year colleges & universities in the U.S.

– 1986-87: $1,414 (1986 CPI = 109.6)– 2006-07: $5,834 (2006 CPI = 203.8)


Correcting Variables for Inflation:Indexation

For example, the increase in the CPI automatically determines– the COLA in many multi-year labor contracts

– the adjustments in Social Security payments and federal income tax brackets

A dollar amount is A dollar amount is indexedindexed for inflation for inflation if it is automatically corrected for inflation if it is automatically corrected for inflation

by law or in a contract.by law or in a contract.


Correcting Variables for Inflation:Real vs. Nominal Interest Rates

The nominal interest rate: – the interest rate not corrected for inflation

– the rate of growth in the dollar value of a deposit or debt

The real interest rate:– corrected for inflation

– the rate of growth in the purchasing power of a deposit or debt

Real interest rate = (nominal interest rate) – (inflation rate)


Correcting Variables for Inflation:Real vs. Nominal Interest Rates

Example:

– Deposit $1,000 for one year.

– Nominal interest rate is 9%.

– During that year, inflation is 3.5%.

– Real interest rate = Nominal interest rate – Inflation= 9.0% – 3.5% = 5.5%

– The purchasing power of the $1000 deposit has grown 5.5%.


Real and Nominal Interest Rates in the U.S.,1950-2007

-10

-5

0

5

10

15

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Inte

rest

Rat

es

(per

cen

t p

er y

ear)

Nominal interest rate Real interest rate

-10

-5

0

5

10

15

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Inte

rest

Rat

es

(per

cen

t p

er y

ear)

Nominal interest rate Real interest rate


What’s up in Korea with CPI?

• Korean CPIWhat is the base year for the given CPI?

10,000 won in 1995 would have been worth how much in 2010?



• CPI Info… (11/11)• By the end of the year, the office will add items that account

for more than one-10,000th of monthly household expenditures; those falling short of the standard will be excluded.

• The statistics agency revises the index, currently comprising 516 items, every five years.

• New Additions This Year• Smart phones, makgeolli (Korean rice beer) and samgak

gimbap (triangular seaweed rice rolls)• Items Removed This Year

• Gold rings, camcorders and public phone calls

• Source: www.seriworld.org



• The country’s average CPI growth for the first 10 months of this year was 4.4 percent compared to 2010. The new CPI system is aimed at lowering inflation for the January-October period by 0.4 percentage points to 4 percent. Critics claim the overhaul is merely an attempt to lower the inflation index, especially given the steep drop. When the government revised the index in 1991, CPI growth fell 0.3 percentage points. Five years later, another slew of amendments saw it fall by 0.1 percentage points, then 0.3 percentage points in 2001 and 0.2 percentage points in 2006.

• Statistics Korea refuted the accusation by countering that the biggest impact to the new CPI gauge would be caused by the omission of gold ring prices, as these have surged recently. With these alone taken out of the equation, the country’s overall CPI growth drops by 0.25 percentage points. The government said it will announce two separate CPIs for November calculated using each of the systems on Thursday.

• Posted on November 11, 2011 on seriworld.org

Summary


• The consumer price index shows the cost of a basket of goods and services relative to the cost of the same basket in the base year.

• The index is used to measure the overall level of prices in the economy.

• The percentage change in the CPI measures the inflation rate.

Summary


• The consumer price index is an imperfect measure of the cost of living for the following three reasons: substitution bias, the introduction of new goods, and unmeasured changes in quality.

• Because of measurement problems, the CPI overstates annual inflation by about 1 percentage point.

Summary


• The GDP deflator differs from the CPI because it includes goods and services produced rather than goods and services consumed.

• In addition, the CPI uses a fixed basket of goods, while the GDP deflator automatically changes the group of goods and services over time as the composition of GDP changes.

Summary


• Dollar figures from different points in time do not represent a valid comparison of purchasing power.

• Various laws and private contracts use price indexes to correct for the effects of inflation.

• The real interest rate equals the nominal interest rate minus the rate of inflation.

Documents

© 2007 Thomson South-Western. Last Chapter … In the last chapter, we looked at how economists use GDP to measure the quantity of goods and services that