Consumer Price Index

Archived Relative Importance of Components in the Consumer Price Indexes

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We produce relative importance of components in the Consumer Price Index for All Urban Consumers (CPI-U) and the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W). These data are to be used in conjunction with the CPI-U and CPI-W released in that same year. BLS publishes this data once a year, using December data. Relative importance data is also published monthly at the U.S. level in the news release tables.

Table 1 contains data for the U.S. city average for all categories. In years where the weights used in the construction of the CPI are updated, table 1 is produced using both the old and new weights to allow users to compare them. Tables 2 through 6 contain data for selected categories for the regions, metropolitan areas, population size classes, and cross-classifications of area and population size class. Table 7 contains the relative importance of the all items index for the U.S. city average and size class, region and region size class, and metropolitan areas.

The relative importance of a component is its expenditure or value weight expressed as a percentage of all items within an area or an area within the U.S. When the value weights are collected they represent average annual expenditures, and their relative importance ratios show approximately how the index population distributes expenditures among the components. Relative importance ratios represent an estimate of how consumers would distribute their expenditures as prices change over time.

Relative importance ratios cannot be used as estimates of current spending patterns or as indicators of changing consumer expenditures in the intervals between weight revisions because consumption patterns are influenced by factors other than price change. These factors include income, variations in climate, family size, and availability of new and different kinds of goods and services.

Relative importance ratios of components in the national or local area Consumer Price Indexes can be used in the construction of indexes for special combinations of items. In such instances, relative importance ratios are used as weights to combine relative changes in prices of the selected components over specified periods.Additional information on the procedure for deriving index weights from consumer expenditure data is available in the Consumer Expenditure Survey and Consumer Price Index sections of the BLS Handbook of Methods.

How to estimate an updated relative importance

To estimate a relative importance for a component for a month other than December, one can use its previous published relative importance and update it by published price changes. For example, suppose you want to estimate the relative importance of energy for the CPI-U in September 2017.

You need the published relative importance for energy for December 2016 and the December 2016 and Sept.ember 2017 indexes for energy and for all items. Enter the weights and indexes for these two item categories (see table A). The updated weight column is the December published weight times the relative change between December 2016 and September 2017. In this example, the updated weight for energy is 7.039 * (215.711/193.306) = 7.8549. For all items, the updated weight is 100.000 * (246.819/241.432) = 102.2313. To calculate the updated relative importance for energy where the weight for all items is normalized to 100, divide the updated weight for energy by the updated weight for all items, times 100. In this example, the estimated relative importance for energy in September 2017 is (7.8549 / 102.2313) X 100 = 7.683.

Table A. Estimating an updated relative importance for energy for September 2017
Item Published relative importance Dec. 2016 Index Dec. 2016 Index Sep. 2017 Updated weight Sep. 2017 Updated weight Sep. 2017 (normalized so that all items=100)

Energy

7.039 193.306 215.711 7.8549 7.683

All items

100.000 241.432 246.819 102.2313 Normalized to 100.000

How to estimate the contribution of a component to the overall price change

Continuing the above example, energy prices increased 6.4 percent over the 12 months ending October 2017, while the all items index increased 2.0 percent. How does one figure out the "contribution" of the energy component to the all items change? Asked another way, what proportion of the all items increase can be attributed to the energy component?

First, estimate the updated relative importance for energy for September 2017 (see the last column in Table A). Second, multiply the updated expenditure weight of energy times its relative price change in October (7.683 X 1.064 = 8.175). Similarly, the updated expenditure weight for all items is 100 X 1.02 = 102.000 (see table B).

The change in the expenditure weight for energy in October is 8.175-7.683=0.492 and the change in the expenditure weight for all items in October is 102.000-100.00=2.000.

The contribution of energy to the all items change equals the change in the expenditure weight for energy divided by the change in the expenditure weight for all items. Specifically, the contribution of energy to all items in this example is 0.492 / 2.000 = 0.246 or 24.6 percent. Said another way, nearly one fourth of the increase in the October index was due to the increase in energy prices.

Table B. Estimating the contribution of energy to the all items change in October 2017
Item Normalized/updated weight for Sep. 2017 (from Table A) Price change from Oct. 2016 to Oct. 2017 (expressed as a relative) Updated weight Oct. 2017 Differences in weights

Energy

7.683 +6.4 percent (1.064) 8.175 10.456-10.352=0.492

All items

100.000 +2.0 percent (1.020) 102.000 102.000-100.000=2.000

Contribution of energy to all items

- - - 0.492/2.000=0.246 (24.6 percent)

Archived Relative Importance Data

  • December 2017
    • Table 1, U.S. City Average using 2015-2016 weights (TXT)
    • Table 1, U.S. City Average using 2013-2014 weights (PDF)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2016
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
    • Table 1, U.S. City Average using 2013-2014 weights (TXT)
  • December 2015
    • Table 1, U.S. City Average using 2013-2014 weights (TXT)
    • Table 1, U.S. City Average using 2011-2012 weights (PDF)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2014
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
    • Table 1, U.S. City Average (TXT)
  • December 2013
    • Table 1, U.S. City Average using 2011-2012 weights (TXT)
    • Table 1, U.S. City Average using 2009-2010 weights (PDF)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2012
    • Table 1, U.S. City Average using 2009-2010 weights (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2011
    • Table 1, U.S. City Average using 2009-2010 weights (TXT)
    • Table 1, U.S. City Average using 2007-2008 weights (PDF)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2010
    • Table 1, U.S. City Average using 2007-2008 weights (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2009
    • Table 1, U.S. City Average using 2007-2008 weights (TXT)
    • Table 1, U.S. City Average using 2005-2006 weights (PDF)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2008
    • Table 1, U.S. City Average using 2005-2006 weights (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2007
    • Table 1, U.S. City Average using 2005-2006 weights (TXT)
    • Table 1, U.S. City Average using 2003-2004 weights (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2006
    • Table 1, U.S. City Average (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2005
    • Table 1, U.S. City Average using 2003-2004 weights (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2004
    • Table 1, U.S. City Average (TXT)
    • Tables 1-7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2003
    • Table 1, U.S. City Average using 1999-2000 weights (TXT)
    • Table 1, U.S. City Average using 2001-2002 weights (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2002
    • Table 1, U.S. City Average (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2001
    • Table 1, U.S. City Average using 1993-1995 weights (TXT)
    • Table 1, U.S. City Average using 1999-2000 weights (TXT)
    • Tables 1 - 7, Relative Importance of Components in the Consumer Price Index, all areas (PDF)
  • December 2000
    • U.S. City Average (TXT)
  • December 1999
    • U.S. City Average (TXT)
  • December 1998
    • U.S. City Average (TXT)
  • December 1997
    • U.S. City Average (TXT)
  • December 1996
    • U.S. City Average (TXT)
  • December 1995
    • U.S. City Average (TXT)
  • December 1994
    • U.S. City Average (TXT)
  • December 1993
    • U.S. City Average (TXT)
  • December 1992
    • U.S. City Average (TXT)
  • December 1991
    • U.S. City Average (TXT)
  • December 1990
    • U.S. City Average (TXT)
  • December 1989
    • U.S. City Average (TXT)
  • December 1988
    • U.S. City Average (TXT)
  • December 1987
    • U.S. City Average (TXT)

 

Last Modified Date: February 9, 2018