The 1998 CPI Revision: Changes in Available Data Series
With release of the Consumer Price Index (CPI) data for January 1998,
the CPI will reflect several program improvements. For example, the area
sample will be updated to reflect the population distribution from the
1990 (instead of 1980) Census. This makes the CPI more useful because the
samples it is based on will better reflect where people now live and shop.
The CPI will also update the expenditure weights used in its market
baskets to represent 1993-95 (instead of 1982-84) spending patterns. New
expenditure weights improve the CPI because consumers change their purchasing
patterns in response to many long-term factors. Without updates the index
would overweight many now infrequently purchased items, such as domestic
service and phonograph records, and underweight many newly important items,
such as adult day care and computer software. In addition, the CPI will,
for the first time, use estimates of index variances as a guideline for
determining which data series will get published.
As a result of the improvements, the list of items and areas for which
CPI data will be available will change. Some of the most significant changes
Effective with the release of the January 1998 Consumer Price Index
(CPI) data in February 1998, the list of items and areas published will
Some areas will change publication cycles.
Many area definitions will change.
There will be eight major groups instead of seven, and the content of some
of the groups will change.
Item categories, definitions, and publication levels will change.
A year later (January 1999), the 1967=100 base will be eliminated.
Although the CPI is a measure of price change for a fixed market basket
of goods and services bought by consumers, periodically BLS updates the
goods and services for which prices are collected, so the CPI will continue
to accurately represent what consumers are buying. In addition, changes
in the population size of various cities and regions must be taken into
account in the CPI structure, so the CPI will accurately reflect the current
population distribution. These periodic adjustments are called "major revisions."
There have been five previous major revisions to the CPI, and another is
scheduled for January 1998. This fact sheet highlights the most important
changes associated with the 1998 CPI Revision and lists additional sources
of information about this revision.
|If you have a contract tied to a local area, the 1967=100
base, or an index series other than "All Items," you will want to see if
the contract remains valid.
Area publication cycle changes
Baltimore and Washington will be combined into one metropolitan
area and will be published on a bimonthly basis for odd (January, March,
etc.) months. After December 1997, separate CPI's will not be published
for either Washington or Baltimore.
Philadelphia and San Francisco, two areas that are now published
monthly, will be changed to a bimonthly basis for even (February, April,
Buffalo and New Orleans will no longer be published.
Pittsburgh and St. Louis will change from bimonthly to semiannual
publication. (Semiannual indexes represent the index for the first—or second—half
of the year and do not represent any single month.)
Seattle and Atlanta will increase their frequency from semiannual
to bimonthly—for even and odd months, respectively—and Tampa will
increase its frequency from annual to semiannual.
There will be a reduction of city-size classes from four to three. The
A population size will represent all metropolitan areas over 1.5 million
(plus Anchorage and Honolulu); B/C will represent smaller metropolitan
areas (1.5 million or less); and D, all nonmetropolitan urban areas.
Area definition changes
Many of the areas will be redefined, based on the new Office of Management
and Budget (OMB) metropolitan area definitions. These changes are hinted
at by some of the changes in area titles. For example, the Detroit-Ann
Arbor, MI area will be retitled the Detroit-Ann Arbor-Flint, MI area. (For
more details, see the list of definition changes for published metropolitan
Major group structure and content changes
There will be eight major groups instead of seven, and the content of most
groups will change. (For more details see the list entitled Highlights
of the CPI Item Structure Changes by Major Group and Main Housing Subgroups.)
Changes in the level of detail published
In addition to changes in area and item definitions, there will be some
reduction in the number of detailed indexes available (especially below
the U.S. city average level), due to limitations in sample size.
Reference base period changes
Effective with the release of the CPI for January 1999, the standard reference
base period will be 1993-95=100. All price changes will be measured from
a reference base (100) that represents the average index level of the 36-month
period encompassing 1993, 1994, and 1995. As a service to our customers
with existing escalation provisions, BLS will continue to publish CPI All
Items indexes for the U.S. city average and all local areas, using the
old 1982-84=100 reference base. Tables of conversion factors and technical
assistance will be available, upon request, to customers. The conversion
factor tables will enable users to derive 1982-84 and later based indexes
from the 1993-95=100 indexes at all levels of index publication. Effective
with the release of the CPI for January 1999, BLS will DISCONTINUE the
publication of 1967=100 based indexes.
For more information
BLS has more detailed information available on the 1998 CPI Revision. For
example, reprints of the December 1996 Monthly Labor Review articles on
the CPI revision are available upon request. For these, or other additional
information about the CPI, please contact any of the eight BLS regional
offices (located in Boston, New York, Philadelphia, Atlanta, Chicago, Dallas,
Kansas City, and San Francisco); call our national information staff at
(202) 606-7000; or write to:
Bureau of Labor Statistics
Internet address: http://stats.bls.gov/cpihome.htm
Division of Consumer Prices and Price Indexes
Room 3615 PSB
2 Massachusetts Ave., NE
Washington, D.C. 20212-0001
Information in this report is in the public domain, and with appropriate
credit, may be used without permission. This information is available to
sensory impaired individuals upon request. Voice phone: (202) 606-7828;
TDD phone: (202) 606-5897; TDD message referral phone:1-800-326-2577.