What Is the Consumer Price Index?

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Inflation is at the top of most people's minds. That's because it affects all areas of consumer spending, employment rates and business investment. It primarily affects interest rates.


But what goes into measuring inflation? Is there a tool that economists use to see where prices are trending?

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Consumer Price Index as Tool

The Consumer Price Index (CPI) is a tool. It looks at consumer goods prices and how these prices are trending. What the CPI measures lets economists see the average percentage change in a specified time that consumers pay for a market basket of goods.


The CPI index shows a measure of inflation. For example, in May 2022, the CPI data showed that consumer price changes were up 8.6 percent from May 2021. This is the highest increase since 1981.

The CPI is one of the tools that the federal reserve uses to determine whether to raise or lower interest rates.


Basket of Goods Indicator

A market basket allows economists to track recession cycles and economic growth. These market baskets are bundled services and goods, often called baskets of goods. They represent categories of items like education, housing, medical care, food, fuel oil, new vehicles, etc.


The items in the basket of goods could adjust to reflect changes in habits within groups of the economy. These different habits could reflect price changes.


According to the Bureau of Labor Statistics (BLS) website, the basket of goods methodology was developed based on surveying population groups and determining what they bought. Based on this historical data, the CPI detects price movements.


The BLS explains that the basket of goods often shows summaries of all urban consumers' behavior. It also shows an overall view of inflation.

What the CPI measures, makes it possible for economists to see the average percentage change in a specified time that consumers pay for a market basket of goods.


Market Baskets of Goods

There are three types of baskets of goods. They are the consumer market basket, the producer price index market basket of goods and the house price index basket of goods.

The consumer basket of goods measures consumer spending, whereas the producer index basket of goods measures selling habits. The house price index basket of goods measures changes of single-family homes according to zip code.



Owners’ Equivalent Rent and CPI

Owners' Equivalent Rent (OER) is the amount of money a homeowner would have to pay in rent to have the same home they currently own. It is a measure of the value of real estate. It can help inform whether it makes more sense to rent or own.


If the Owners' Equivalent Rent is high, then buying a home is worthwhile. Suppose it is low, then you should rent. The OER generally changes when there is movement in the CPI. There is a link between the Owners' Equivalent Rent and inflation.

Chained Consumer Price Index

The Chained Consumer Price Index for all urban consumers (C-CPI-U) uses a formula to measure substitutions that all urban consumers make across categories when responding to relative price changes.


Historically, the CPI didn't reflect changes in consumer behavior. The C-CPI-U allows for these changes to be measured.

Difference Between CPI-U vs. CPI-W

The CPI-U measures all urban consumers. These are defined as households in the U.S. that aren't located in metropolitan areas, military installations, farm households, religious communities or in institutions like mental hospitals or prisons.



CPI-U consumers include the self-employed, professionals, the unemployed, retired people, urban wage earners and clerical workers. This group makes up approximately 89 percent of the U.S. population.

The CPI-W measures change for urban consumers where more than one-half of the household's income derives from clerical or wage occupations and where at least one of the household earners has been employed for 37 weeks in the previous 12 months. This is 28 percent of the U.S.

They may sound similar, but in reality, the CPI-W is measuring a price change for "blue-collar" workers that live in an urban area. The CPI-U measures a price change for all urban consumers.

Cost-of-Living Index

A Cost-of-Living Index is meant to compare expenses from one city or region to another. These expenses include medical care, utilities, childcare, food, housing, etc. A Cost-of-Living Index can be used to track how these expenses rise over time.

A Cost-of-Living Adjustment is an increase in your pay that is determined by the overall Cost-of-Living in an area.




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