TECHNICAL NOTE


Import and Export Merchandise and Services Price Indexes -- All indexes use a modified Laspeyres 
formula and are not seasonally adjusted.  Price indexes for merchandise goods are reweighted annually, 
with a two-year lag in the weights.  Published series use a base year of 2000=100 where possible.  More 
detailed index series and additional information may be obtained at http://www.bls.gov/mxp, or by 
calling (202) 691-7101.

Merchandise Goods Classification Systems -- The merchandise price indexes are published using 
three classification systems.  Items are classified by end use according to the Bureau of Economic 
Analysis Classification System, by industry according to the North American Industry Classification 
System (NAICS), and by product category according to the Harmonized System (HS).  While 
classification by end use and product category are self-explanatory, some notes are in order for 
classifying items by industry.  In the NAICS imports and exports tables, items are classified by output 
industry, not input industry.  As an example, NAICS import index 326 (plastics and rubber products 
manufacturing) include outputs such as manufactured plastic rather than inputs such as petroleum.  The 
NAICS classification structure also matches the classification system used by the PPI (Producer Price 
Index) to produce the NAICS primary products indexes.

Import Price Indexes -- Products have been classified by the Harmonized Tariff Schedule of the United 
States Annotated (TSUSA).  Import prices are based on U.S. dollar prices paid by the U.S. importer.  
The prices are generally either "free on board" (f.o.b.) foreign port or "cost, insurance, and freight" 
(c.i.f.) U.S. port transaction prices, depending on the practices of the individual industry.  The index for 
crude petroleum is calculated from data collected by the U.S. Department of Energy.  

Export Price Indexes -- Products have been classified by the Harmonized Schedule B classification 
system of the U.S. Bureau of the Census.  The prices used are generally either "free alongside ship" 
(f.a.s.) factory or "free on board" (f.o.b.) transaction prices, depending on the practices of the individual 
industry.  Prices used in the grain index, excluding rice, are obtained from the U.S. Department of 
Agriculture.

Services Price Indexes -- Starting in September 2008 the Import Air Passenger Fares Indexes represent 
changes in the average revenue per passenger received by foreign carriers from U.S. residents and are 
calculated from data obtained from an airline consulting service.  These data include tickets sold by 
travel agencies and travel websites.  Tickets sold directly by the airlines are excluded, as are frequent 
flyer tickets generally.  Starting in January 2008 the Export Air Passenger Fares Indexes represent 
changes in the average revenue per passenger received by U.S. carriers from foreign residents and are 
calculated from data collected directly from airlines. These data include frequent flyer tickets and those 
sold by consolidators. Taxes and fees are excluded from both indexes. The Air Freight Indexes are 
calculated from data collected directly from airlines. These data exclude mail and passenger baggage. 
The scope of the service being priced is the movement of freight from airport to airport only, and does 
not include any ground transportation or port service. The Air Freight Indexes are presented using two 
definitions: Balance of Payments (which represent transactions between U.S. and foreign residents) and 
International (which represent transactions inbound to and outbound from the U.S.). Fact sheets 
specifying detailed information for each services industry are available at http://www.bls.gov/mxp under 
"MXP Publications".

Import Indexes by Locality of Origin -- Prices used in these indexes are a subset of the data collected 
for the Import Price Indexes.  Beginning with January 2002, the indexes are defined by locality of origin 
using a nomenclature based upon the North American Industry Classification System (NAICS).  
Nonmanufactured goods are defined as NAICS 11 and 21 and manufactured goods are defined as 
NAICS 31-33. 
 
Revision Policy -- To reflect the availability of late reports and corrections by respondents, monthly data 
may be revised in each of the three months after original publication.  After three months, no further data 
revisions take place.  So, for example, data released in the January release will be subject to revision in 
the releases for February, March, and April.

Uses of the Data -- The primary use of the indexes is to deflate trade statistics, notably the foreign trade 
sector of the National Income and Product Accounts constructed by the Department of Commerce.  
Other published indexes are useful for general market analysis.  For trade in international services, 
Balance of Payments indexes are used for deflating National Income and Product Accounts, while 
International indexes are more appropriate for market analysis.  Merchandise and services indexes also 
can be used to study U.S. competitiveness and to compute price elasticities, and the merchandise import 
indexes by country or region of origin are useful in terms of trade analysis.

E-Mail Subscription -- The IPP news release is available through an e-mail subscription service at 
(http://www.bls.gov/mxp) or (http://www.bls.gov/bls/newsrels.htm).
 
Additional Information -- More detailed IPP data are available on the IPP home page at 
(http://www.bls.gov/mxp).  Flat Files and the FTP server are available for users requiring access to 
either a large volume of time series data or other IPP-related documentation. The FTP site can be 
accessed at ftp://ftp.bls.gov.   For technical assistance in using the BLS Internet site, send e-mail to 
(labstat.helpdesk@bls.gov).  For IPP data requests, send e-mail to (mxpinfo@bls.gov). 

Information from this release will be made available to sensory impaired individuals upon request.  
Voice phone: 202-691-5200; Federal Relay Service: 1-800-877-8339.