The consumer price index (CPI) during the month of October 2003 did not change. The rate of increase in the consumer price index over the past twelve months has been 2.0 percent. In October, the core consumer price index, which excludes energy and food prices, increased by 0.2 percent.


Consumer Economics, Consumer Price Index (CPI), Consumers, Deflation, Full Employment, Inflation, Monetary Policy, Money, Unemployment

Current Key Economic Indicators

as of November 30, -0001


The consumer price index (CPI) during the month of October 2003 did not change. The rate of increase in the consumer price index over the past twelve months has been 2.0 percent.

In October, the core consumer price index, which excludes energy and food prices, increased by 0.2 percent.

Information for Teachers

All paragraphs in italics will not appear in the student version of the inflation case study. This case builds upon the previous inflation case study. More advanced concepts and questions will be added throughout the fall semester.

The original press release can be found at .

This lesson uses several charts and tables. You may use these files to create student reproducables or overhead transparencies for use in your classroom.

Goals of the Case Study

The goals of the Inflation Case Studies are to provide teachers and students:

  • access to easily understood, timely interpretations of monthly announcements of rate of change in prices in the U.S. economy;
  • descriptions of major issues surrounding the data announcements;
  • brief analyses of historical perspectives;
  • questions and activities to use to reinforce and develop understanding of relevant concepts; and
  • a list of publications and resources that may benefit classroom teachers and students interested in exploring inflation.

Definitions of Inflation

Inflation is a sustained increase in the overall level of prices. The most widely reported measurement of inflation is the consumer price index (CPI). The CPI measures the cost of a fixed basket of goods relative to the cost of that same basket of goods in a base (or previous) year. Changes in the price of this basket of goods approximate changes in the overall level of prices paid by consumers.

Data Trends

In October, the Consumer Price Index did not change, after increasing by 0.3 percent in August and in September. In October, increases in the prices of medical care, food, housing, and apparel caused inflation to increase, while a downturn in the prices of transportation (primarily due to reduced fuel costs) balanced those increased prices.

The core rate of inflation (0.2 percent in October) represents the consumer price index without the influences of changes in the prices of food and energy, which can fluctuate widely from month to month. The October increase compares to a 0.1 percent increase in the core rate of inflation in August and in September. Core prices actually increased more rapidly this month than the overall index because energy prices fell.

Figure 1 below shows recent inflation data reported for each month. Inflation increased in 1999 and 2000 when compared to1998, slowed throughout much of 2001, and then has increased slightly in 2002. What is really quite obvious from Figure 1 is that the changes in inflation from month to month are much more dramatic from 1999 on, when compared to 1998. The increased volatility is primarily due to fluctuations in the prices of oil and food. The core rate of inflation (excluding food and energy) gives a much better idea of longer-term trends and that is why it is often featured in news reports. See figure 2.

Figure 1: Monthly Inflation in Consumer Prices at Annual Rates

Figure 2: Monthly Core Inflation Rate (excludes food and energy)

Compared to the rates of inflation in the 1970s and much of the 1980s, the current rate of inflation is quite low. See figure 3 below. Few observers would describe the most recent rates as high and they are not, when compared to those of the past thirty years. Other observers would describe the current experience as no or zero inflation.

The Consumer Price Index

The seasonally adjusted consumer price index in October was 185.0. The price index was equal to 100 during the period from 1982 to 1984. The interpretation is that prices in market basket of goods purchased by the typical consumer increased from the 1982-1984 period to October 2003 by 85.0 percent.

Inflation is usually reported in newspapers and television news as percentage changes in the CPI on a monthly basis. For example, the CPI in September was 185.0, compared to 184.5 in August. The increase in prices from August to September was ( 185.0 -184.5) / 184.5 = 0.0027 or a monthly inflation rate of .0.27 percent. It is reported to the nearest one-tenth of a percent, in this case, 0.3 percent. To convert this into an annual rate, you could simply multiply by 12. This approximates an annual inflation rate of (0.3) (12) = 3.6 percent. A slightly more accurate measurement of the annual inflation rate is to compound the monthly rate, or raise the monthly rate of increase, plus one, to the 12th power.

Month Price Level Monthly Inflation Rate Annual Inflation Rate
How the Annual Inflation Rate is Calculated
September 185.0
185.0 – 184.5 = .0027 or .3 %

1.002712 = 1.033 or 3.3 %
August 184.5

How the CPI Data are Collected

"The Consumer Price Index (CPI) is a measure of the average change in prices over time of goods and services purchased by households. The CPI is based on prices of food, clothing, shelter, and fuels, transportation, fares, charges for doctors' and dentists' services, drugs, and other goods and services that people buy for day-to-day living.

“Prices are collected in 87 urban areas across the country from about 50,000 housing units and approximately 23,000 retail establishments - department stores, supermarkets, hospitals, filling stations, and other types of stores and service establishments. All taxes directly associated with the purchase and use of items are included in the index. Prices of fuels and a few other items are obtained every month in all 87 locations.

“Prices of most other commodities and services are collected every month in the three largest geographic areas and every other month in other areas. Prices of most goods and services are obtained by personal visits or telephone calls of the Bureau's trained representatives.” For more information on the Bureau of Labor Statistics, visit ( ).

A Note on Seasonally Adjusted and Unadjusted Data

"Because price data are used for different purposes by different groups, the Bureau of Labor Statistics publishes seasonally adjusted as well as unadjusted changes each month. For analyzing general price trends in the economy, seasonally adjusted changes are usually preferred since they eliminate the effect of changes that normally occur at the same time and in about the same magnitude every year--such as price movements resulting from changing climatic conditions, production cycles, model changeovers, holidays, and sales.

The unadjusted data are of primary interest to consumers concerned about the prices they actually pay. Unadjusted data also are used extensively for escalation purposes. Many collective bargaining contract agreements and pension plans, for example, tie compensation changes to the Consumer Price Index unadjusted for seasonal variation." ( )

An Exercise for Understanding the Definition of Inflation

The following question and answer appeared in a recent publication of a major financial firm.

“Have you experienced inflation recently? How was the inflation caused?

“Suggested answer: Recent increases in gas prices; prices of fruits and vegetables varying with seasons; bathing suits costing more in the spring and summer, movie ticket prices being less or more depending on the area….”

Can you evaluate the question and answer?

A better analysis focuses on the definition of inflation. Inflation is a sustained increase in the overall level of prices. In a market economy, prices vary in different seasons and in different areas. There are always some prices increasing and others decreasing as demand and supply conditions change in the markets. Inflation is an increase in average or overall price levels. It is not increases in specific markets or differences in prices in seasons or areas as described in the above question and answer.

Costs of Inflation

Understanding the costs of inflation is not an easy task. There are a variety of myths about inflation. There are debates among economists about some of the more serious problems caused by inflation. A number of exercises in National Council on Economic Education publications, student workbooks, and textbooks should help students think about the consequences of inflation.

  1. High rates of inflation mean that people and business have to take steps to protect their financial assets from inflation. The resources and time used to do so could be used to produce goods and services of value. Those goods and services given up are a true cost of inflation.
  2. High rates of inflation discourage businesses planning and investment as inflation increases the difficulty of forecasting of prices and costs. As prices rise, people need more dollars to carry out their transactions. When more money is demanded, interest rates increase. Higher interest rates can cause investment spending to fall, as the cost of investing increases. The unpredictability associated with fluctuating interest rates makes customers less likely to sign long-term contracts as well.
  3. The adage “inflation hurts lenders and helps borrowers” only applies if inflation is not expected. For example, interest rates normally increase in response to anticipated inflation. As a result, the lenders receive higher interest payments, part of which is compensation for the decrease in the value of the money lent. Borrowers have to pay higher interest rates and lose any advantage they may have from repaying loans with money that is not worth as much as it was prior to the inflation.
  4. Inflation does reduce the purchasing power of money.
  5. Inflation does redistribute income. On average, individuals' incomes do increase as inflation increases. However, some peoples' wages go up faster than inflation. Other wages are slower to adjust. People on fixed incomes such as pensions or whose salaries are slow to adjust are negatively affected by unexpected inflation.

Causes of Inflation

Over short periods of time, inflation can be caused by increases in costs or an increase in spending. Inflation resulting from an increase in aggregate demand or total spending is called demand-pull inflation . Increases in demand , particularly if production in the economy is near the full-employment level of real GDP, pull up prices. It is not just rising spending. If spending is increasing more rapidly than the capacity to produce, there will be upward pressure on prices.

Inflation can also be caused by increases in costs of major inputs used throughout the economy. This type of inflation is often described as cost-push inflation . Increases in costs push prices up. The most common recent examples are inflationary periods caused largely by increases in the price of oil. Or if employers and employees begin to expect inflation, costs and prices will begin to rise as a result.

Over longer periods of time, that is, over periods of many months or years, inflation is caused by growth in the supply of money that is above and beyond the growth in the demand for money.

Inflation, in the short run and when caused by changes in demand, has an inverse relationship with unemployment. If spending is rising more slowly than capacity to produce, unemployment will be rising and there will be little demand-pull inflation. If spending is rising faster than capacity, unemployment is likely to be falling and demand-pull inflation increasing.

That relationship disappears when inflation is primarily caused by increases in costs. Unemployment and inflation can then rise simultaneously.

Other Measures of Inflation

The GDP price index (sometimes referred to as the implicit price deflator). The GDP price index is an index of prices of all goods and services included in the gross domestic product. Thus the index is a measure that is broader than the consumer price index.

The producer price index . This index measures prices at the wholesale or producer level. It can act as a leading indicator of inflation. If the prices producers are charging are increasing, it is likely that consumers will eventually be faced with higher prices for good they buy at retail stores.

A Market Basket of Goods and Services

The Consumer Price Index measures prices of goods and services in a market basket of goods and services that is intended to be representative of a typical consumer's purchases. The percentages that are currently used to describe the categories of goods and services that market basket are as follows.

A Market Basket of Goods and Services




Food and beverages


Medical care




Education and communication




Other goods and services


Using the CPI as an Inflation Index

The Social Security Administration announced on October 16 that Social Security payments, beginning at the end of December, 2003, will increase by 2.1 percent. Annual changes in Social Security payments are based on changes in the consumer price index. The rate of change in consumer prices from October of one year through September of the next is used to calculate the appropriate change in the Social Security payments for the following year. The purpose of the adjustment is to maintain the real purchasing power of the Social Security payments, that is, to reduce the cost of inflation for those who might otherwise be living on fixed incomes.

Income tax brackets and deductions also change according to changes in the consumer price index. Private contracts often also reference changes in inflation as measured by the consumer price index.

Using the CPI –

  1. Given the following data, calculate the rate of inflation between 2001 and 2002.
    1998 163.0
    1999 166.6
    2000 172.2
    2001 177.1
    2002 179.9

    Average per capita disposable income
    1998 $ 23,037
    2001 $ 25,957

    [1.6 percent. 179. / 177.1 = 1.016 or an increase of 1.6 percent.]

  2. Given the above data, calculate the average rate of inflation between 1998 and 2002.

    [ 2.6 percent. 179.9 / 163 = 1.104 or an increase of 10.4 percent. The annual average increase can be approximated by dividing 10.4 percent by four (years) and thus get 2.6 percent per year.]

  3. Using the above data, calculate average real income in 1998 and 2001. Did real per capita income increase or decrease from 1998 to 2001?

    [The real incomes, in 1982-1984 dollars, are calculated as follows:

    Real income in 1998 = $23,037 / 1.630 = $14,133.
    Real income in 2001 = $25,957 / 1.771 = $14,657.

    Yes, real income did increase, but not by almost $3,000, the difference between the nominal incomes. ]

Questions for Students

  1. What is inflation?

    [A continual increase in the average price level. The important points are that most prices or average prices rise and that the increase continues and is not just a one-time increase.]

  2. Calculate a consumer price index in 2002 for the following market basket of goods (using 2003 as a base year).
    3 boxes of cheerios   $4.00 each
    2 pounds of bananas   $1.00 per pound
    2 gallons of milk   $3.00 per gallon
    4 boxes of cheerios   $5.00 each
    1 pounds of bananas   $2.00 per pound
    2 gallons of milk   $3.00 per gallon


    [100. For the base year, the price index is calculated by first taking the 2002 quantities times the 2002 prices. As it is the base year, that number is divided by itself and multiplied by 100. ]

  3. Calculate a consumer price index in 2003 (using 2002 as a base year).

    [125. The price index is calculated by first taking the 2002 quantities times the 2002 prices. The 2003 prices are then multiplied by the 2002 quantities. Then the latter (the amount spent if only the prices change) is divided by the 2002 prices times 2002 quantities and multiplied by 100. ($25/$20) x 100 = 125. The most common mistake will be to calculate the second year with the 2003 prices and 2003 quantities.]

  4. Given this market basket, what is the annual rate of inflation from 2002 to 2003?

    [25 percent. The 2002 index is subtracted from the 2003 index and the difference is divided by the 2002 index. (125-100)/100 = .25 or 25 percent. An easier way, given that the first year is the base year of 100 is simply to compare the two directly. An index of 125 means that prices have gone up by 25 percent since the base year.]

  5. Suppose the CPI was 150 for July of one year, and was 170 for July of the next year. What is the corresponding annual rate of inflation?

    [The rate of increase in prices from over the year can be calculated by dividing the increase in the index by the initial level of the index. (These indexes show a much higher rate of inflation than the actual.)

    That is (170 - 150) / 150 = .133 or 13.3 percent. Because this is over a twelve-month period, it is an annual rate of inflation. More difficult interpretations are based on single month changes. The results are normally converted to annual rates of inflation.]

  6. The base year of the CPI is 1982-1984. What has happened to prices since 1970 if the 1970 index was approximately 80 and if the current CPI were 160?

    [A current level of 160 would mean that consumer prices on average are 100 percent higher than their 1970 levels. The percentage increase is (160 - 80) / 80 = 1 or 100 percent. The base year period is not relevant to the calculation.]

  7. If prices increase by five percent in a year, what effect does this have on the purchasing power of individuals in the economy?

    [Students may answer that purchasing power goes down since their money is worth less, and consequently they cannot buy as many goods and services. The value of money does fall. However, they are ignoring that inflation affects wages as well. If average incomes and prices of goods and services have increased by five percent, the purchasing power of average income remains unchanged.]

  8. What are the costs of increased rates of inflation?

    [Large increases in the price level make it difficult for businesses to estimate future levels of revenues and costs of products. This may discourage some businesses from expanding and making investment decisions. In addition, real income may be redistributed as some incomes rise parallel to or faster than rates of inflation and others are slower to rise. Higher inflation rates lead to higher interest rates. As a result, more resources will be devoted to managing financial assets. Those resources could be used in times of lower inflation to produce other goods and services.]