In this article, we will discuss Consumer Price Index (Definition). So, let’s get started.
The Consumer Price Index
The Consumer Price Index (CPI) is a measure that examines the weighted average of prices of a basket of consumer goods and services, such as transportation, food, and medical care. It is calculated by taking price changes for each item in the predetermined basket of goods and averaging them. Changes in the CPI are used to assess price changes associated with the cost of living.
The CPI is one of the most frequently used statistics for identifying periods of inflation or deflation. It may be compared with the producer price index (PPI), which instead of considering prices paid by consumers looks at what businesses pay for inputs.
Inflation is the decline of purchasing power of a given currency over time; or, alternatively, a general rise in prices. A quantitative estimate of the rate at which the decline in purchasing power occurs can be reflected in the increase of an average price level of a basket of selected goods and services in an economy over some period of time. The rise in the general level of prices, often expressed as a percentage, means that a unit of currency effectively buys less than it did in prior periods.
The CPI is what is used to measure these average changes in prices over time that consumers pay for goods and services. Essentially the index attempts to quantify the aggregate price level in an economy and thus measure the purchasing power of a country’s unit of currency. The weighted average of the prices of goods and services that approximates an individual’s consumption patterns is used to calculate CPI. A trimmed mean may be used as part of this calculation.
The U.S. Bureau of Labor Statistics (BLS) reports the CPI on a monthly basis and has calculated it as far back as 1913. It is based upon the index average for the period from 1982 through 1984 (inclusive) which was set to 100. So a CPI reading of 100 means that inflation is back to the level that it was in 1984 while readings of 175 and 225 would indicate a rise in the inflation level of 75% and 125% respectively. The quoted inflation rate is actually the change in the index from the prior period, whether it is monthly, quarterly or yearly.
While it does measure the variation in price for retail goods and other items paid by consumers, the Consumer Price Index does not include things like savings and investments, and can often exclude spending by foreign visitors.
