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Anchorage, AK (MSA) |
Cincinnati-Hamilton, OH-KY-IN (CMSA) |
Denver-Boulder-Greeley, CO (CMSA) |
Honolulu, HI (MSA) |
Kansas City, MO-KS (MSA) |
Milwaukee-Racine, WI (CMSA) |
Minneapolis-St. Paul, MN-WI (MSA) |
Pittsburgh, PA (MSA) |
Portland-Salem, OR-WA (CMSA) |
St. Louis, MO-IL (MSA) |
San Diego, CA (MSA) |
Tampa-St. Petersburg-Clearwater, FL (MSA) |
Population coverage
For each published CPI data series, two
separate indexes are available: All Urban Consumers (CPI-U) and Urban Wage Earners and
Clerical Workers (CPI-W). Both the CPI-U and the CPI-W reflect only the buying habits of urban
consumers. The CPI-U is the most comprehensive of the two and represents the expenditures
by all urban consumers, about 87 percent of the total U.S. population.
The CPI-W represents a subset of the CPI-U
population, that is, the expenditures by urban households that derive more than one-half
of their income from clerical or hourly wage occupations. These households comprise about
32 percent of the total U.S. population.
Reference Base
The CPI is a tool that simplifies the
measurement of changes in prices over time. By selecting an appropriate reference base and
setting the average index level for that time period equal to 100, it is possible to
compare this months (or last years) price index level with the reference base
period or to any other time period. The current standard reference base period is
1982-84=100. That is, all price changes are measured from a base (100) that represents the
average index level of the 36-month period encompassing 1982, 1983, and 1984.
Prior to the release of the CPI for
January 1988, the standard reference base was 1967=100. As a service to our customers with
existing escalation provisions, BLS continues to publish CPI all items indexes
for the U.S. city average and all local areas using the old base. Note that, although
comparisons cannot be made between indexes with different reference bases, the conversion
to a new reference base does not affect the measurement of percent changes in a given
index series from one time period to another, except for rounding differences.
In addition, BLS publishes several index
series with a reference base more recent than January 1982. These indexes either could not
be rebased because historical price data were not available for the entire 1982-84
reference base period or they represent items (such as mid-grade gasoline) that only
recently were introduced into the CPI.
The CPI market basket
The CPI market basket represents all the
consumer goods and services purchased by urban households. Price data are collected for
over 180 categories, which BLS has grouped into 8 major groups. These major groups, with
examples of categories in each, are as follows:
Food and beverages (ham, eggs,
carbonated drinks, coffee, meals and snacks);
Housing (rent of primary residence,
fuel oil, bedroom furniture);
Apparel (mens shirts and
sweaters, womens dresses, jewelry);
Transportation (new vehicles,
gasoline, tires, airline fares);
Medical care (prescription drugs
and medical supplies, physicians services, eyeglasses and eye care, hospital
services);
Recreation (television sets, cable
TV, pets and pet products, sports equipment, admissions);
Education and communication
(college tuition, postage, telephone services, computer software and accessories);
Other goods and services (tobacco
and smoking products, haircuts and other personal care services, funeral expenses).
Indexes for all of the above categories
are published at the U.S. city average level. Due to limitations in sample size, however,
many of the smaller expenditure categories are not available at regional and local area
levels. Instead, related categories are aggregated and published as part of a more
comprehensive category. For example, physicians services and eyeglasses and eye care
are combined with similar categories and published as professional medical services
at the regional level. At the metropolitan area level, professional medical services is,
in turn, combined further and published as medical care.
Seasonal adjustment
Many of the goods and services included in
the CPI market basket exhibit "seasonal" patterns of price movement. BLS factors
out the seasonal trends from the underlying change in prices and publishes the resulting
seasonally adjusted price indexes for those goods and services that display consistent
seasonal patterns of price change.
BLS publishes seasonally adjusted indexes
only at the U.S. city average level (for both the CPI-U and CPI-W). They are not available
for regional or local area levels. Seasonally adjusted indexes are not appropriate for
use in escalation or cost-of-living adjustments (COLAs) because what consumers actually
pay for goods and services is represented by the unadjusted data.
Additional information
Additional information on the CPI can be
found on the CPI Internet web site (http://www.bls.gov/cpi/).
You may also contact any of the eight BLS regional offices (located in Boston, New York,
Philadelphia, Atlanta, Chicago, Dallas, Kansas City, and San Francisco); or call our
national information staff at (202) 691-7000.
Information in this report is in the public domain and,
with appropriate credit, may be reproduced without permission. This information is
available to sensory impaired individuals upon request. Voice phone: (202) 691-5200; Federal Relay Service: 1-800-877-8339.
Last Modified Date: October 16, 2001
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