Use percent change from month (or quarter) one year ago to show changes over a 12-month (four-quarter) period. Such changes are frequently used to eliminate seasonal patterns from series that have not been seasonally adjusted. Most of the NIPA series that BEA publishes have been seasonally adjusted. Examples of use of these changes include:

  • The price index for core PCE (PCE less food and energy) increased 1.3 percent for the 12 months ending in December 2003. (Such percent changes may be found in table 11 of the personal income and outlays news release.) {NOTE: This is different than the year-to-year percent change from 2002 to 2003, which measures the percent change in prices for core PCE for all of 2003 relative to prices for core PCE for all of 2002. Thus, statements, such as “prices for core PCE increased 1.3 percent in 2003,” when the writer means over the 12 months of 2003, may be misunderstood.} 
  • Residential investment increased 11.8 percent from the fourth quarter of 2002 to the fourth quarter of 2003. (Such percent changes may be found in table 8 of the GDP news release.) {NOTE: This is different than the year-to-year percent change from 2002 to 2003, which measures the percent change in residential investment for all of 2003 relative to all of 2002. Thus, statements, such as “residential investment increased 11.8 percent in 2003,” when the writer means over the four quarters of 2003, may be misunderstood.}

Link to NIPA Tables

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