1.5. Metropolitan Data MethodologyMetro Data Methodology
All state and metro area export values released in the Metropolitan Export Series and related reports are from the U.S. Census Bureau's Origin of Movement–ZIP code Based Series (OM-ZIP). This series, which the Census Bureau reintroduced in 2006, allocates exports to states and localities based on the address of the United States Principal Party in Interest (USPPI) of record.
This is not necessarily the entity that produced the merchandise; hence, the series does not furnish complete and reliable data on the production origin of U.S. exports.
The USPPI of record, as determined from the electronic export information entered into the Automated Export System, is the person or legal entity in the U.S. that receives the primary benefit, monetary or otherwise, from the transaction. Generally, that person or entity is the U.S. seller, manufacturer, or order party, or the foreign entity purchasing or obtaining the goods for export while in the U.S.
The OM-ZIP series can track export sales of states, metropolitan areas, and ZIP codes (at the three-digit level). Statistics are available for exports of goods only. No sub-national data currently exist on exports of services. A state import series measures goods imports down to a state level. However, the zip code information needed to track the imports at a metropolitan area level is not collected at this time.
Data users should be aware that all sub-national export statistics in this series are based on initial data compiled from U.S. export declarations. Subsequent revisions by the Census Bureau (e.g., carryover and annual revisions) are not reflected in the numbers. The tables on these pages, as well as other reports issued by the ITA, make no attempt to adjust the data to eliminate the "unreported" category.
For more information on state export data, see the State Trade Data or go to the Census Bureau’s State Trade Data website.
More detailed data are also available from the Bureau on a fee-for-service basis. Additional questions should be directed to:
U.S. Census Bureau
Economic Statistical Methods Division
International Trade Evaluations Branch
Washington, DC 20233
Metropolitan Statistical Area Data
All metropolitan Core Based Statistical Area (CBSA) export numbers in these tables were tabulated by matching the five-digit ZIP codes entered on U.S. export declarations with the five-digit ZIP codes specified for each metropolitan CBSA using concordance files from the Census Bureau and the U.S. Postal Service. The boundaries of official metropolitan CBSAs are county-based and defined by the Office of Management and Budget (OMB) every 10 years based on population counts taken during the decennial census. The 2013 metropolitan export data was the first year to reflect updated CBSA definitions based on the 2010 Census. As a result, starting with the 2013 data some metropolitan areas no longer met the criteria to be considered a “Metropolitan Statistical Area” (MSA) and a number of new metropolitan areas were added to the data series.
In 2005, there were cases where two or more adjacent metro areas shared the same five-digit ZIP code which made it impossible to assign export transactions with that ZIP code to any single MSA. In these cases, export transactions for the ZIP code in question were assigned to a catch-all “crossovers” category. The crossovers category in 2005 accounted for about 2 percent of total U.S. merchandise exports. In 2006, the OMB eliminated this issue and assigned a single MSA to each five-digit ZIP code. Therefore there is no “crossover” category after 2005.
Because the boundaries of official MSAs are county-based, users can readily determine the coverage of export statistics for any given MSA by referring to published maps or other widely available references. OMB makes available statistical guidelines and a comprehensive list of the current area definitions online and the Census Bureau publishes online files covering both the current and historical delineations.
Because of the relative precision of the five-digit ZIP code method used to compile these tables, the MSA export figures in the Metropolitan Export Series and associated reports can be compared and used in conjunction with any other metropolitan CBSA-based federal statistics (e.g., on population, income, educational level). The only limitation is that the numbers presented here only cover metropolitan CBSAs.
Regarding comparability with other U.S. trade data, the export figures in this publication can be used in conjunction with the OM-ZIP–based state-level data issued by the U.S. Census Bureau. Using these data together it is possible, for example, to show Cleveland's share of Ohio's export sales. However, OM-ZIP data should not be compared to sub-national statistics compiled on an OM-State basis.
In tabulating the MSA export figures, the Census Bureau was unable to allocate value to any local jurisdiction on a limited number of transactions. These totals are aggregated into the category called "unknown”. The totals for 2005, 2006, and 2007 were $39.3 billion (4.3 percent), $42.6 billion (4.1 percent), and $46.2 billion (4.0 percent) of U.S. export totals respectively. For 2008, "unknown" transactions accounted for $49.5 billion (3.8 percent) of U.S. export totals. No “unknown” transactions were recorded after 2008.
Apart from the issues of "crossover" and "unknown" ZIP codes, some exports originate outside of metropolitan (i.e. rural) areas. These transactions are summarized in the "non-metropolitan areas" category, which is displayed where appropriate.
Because of U.S. laws that preclude disclosure of confidential business data provided to the federal government, it is necessary for the U.S. Census Bureau to completely suppress data for certain MSAs each year. These totals are shown as ‘NA’. The totals for these MSAs have been folded into a category labeled "other metropolitan areas”. These suppressions are described in Metropolitan Data Suppressions.
For the 386 metro areas for which it is possible to release some export data, disclosure regulations still limit or prevent the release of much detail on foreign markets and the industry composition of exports. Manufactured product detail, even for the largest exporting MSAs, is limited to broad four-digit NAICS (North American Industry Classification System) categories. Information on market destinations is also subject to important disclosure-induced limitations. Disclosure-induced limitations, other than those for total exports, are shown as ‘D’.