Sectoring schemes provide a means of combining and classifying Industrial data, and each database type has a unique format for grouping and classifying Industries (e.g.  IMPLAN scheme, or the REIS scheme).  In general, an Industrial classification scheme allows categorization according to the type of products or services produced by the Industry(s).

All Employment and Value Added data used in IMPLAN originates in a government report or survey of a single establishment. This establishment may be a small business with a single location, or it may be a branch location of a large firm. Each establishment, in the defined region, is counted separately on the Unemployment or Social Security rolls. When the establishment submits an unemployment report or responds to a census or a survey, it data is collected by the requesting agency and assigned an establishment code depending on the primary product produced by that establishment.

The industry classification scheme used for all federal government industry based data sets is the 6-digit North American Industrial Classification Scheme (NAICS), as described in the 2007 NAICS manual, pbulished by the Office of Management and Budget.

This scheme was adopted in 1997/98 replacing the previously-used Standard Industrial Classification (SIC) codes.  Unlike the SIC, NAICS was developed jointly by the United States, Mexico, and Canada to allow for comparability between all North American Industrial data.

The current NAICS scheme is 2007.  There are two previous versions of the NAICS system: 1997 and 2002.  NAICS reports five levels of Industry detail, ranging from the 2-digit detail (the most aggregate) to the 6-digit (the most detailed).  To learn more about the history of NAICS click here.

Another other major dataset used to derive IMPLAN databases is from the Bureau of Economic Analysis’s Regional Economic Accounts (REA). At the state level,  REA reports in 3-digit NAICS detail for employment and income.  However, at the county level, income is reported at the 3-digit NAICS but employment is only provided at the 2-digit NAICS detail.

Data from the Bureau of Labor Statistics (BLS) is used for deflators and some output estimates. The BLS uses a different sectoring scheme, again based on the NAICS code system.

IMPLAN's current 440-sector scheme is based on the Bureau of Economic Analysis’s latest Benchmark Input-Output Study.  This scheme is nearly 6-digit NAICS for manufacturing and more aggregate for service sectors.  The major difference is the number of retail sectors.  The current BEA Benchmark study is 2002.

Prior to NAICS, this was the most common scheme as described in the 1987 Standard Industrial Classification Manual. This scheme had four levels of detail ranging from 1-digit detail as the most aggregate to 4-digit as the most detailed.  IMPLAN datasets prior to 2001 are SIC-based.

Because IMPLAN Sectoring is linked to the BEA Benchmark I-O, with each new Benchmark release the IMPLAN Sectoring scheme is modified.  Original Sectoring schemes included 528 sectors.  With the release of the 1997 Benchmark, this shifted to 509 Sectors, and then with the release of the 2002 Benchmark (corresponding with IMPLAN 2007 data release year) a movement to 440 Sectors. It is important to remember that certain Sectors have special definitions, and don't follow the same "rules" as the standard IMPLAN Sectors. These special Sectors are noted below.  Additionally, Construction Sectors in IMPLAN are based on Census structure types rather than NAICS codes.

For a more detailed description of 2007 NAICS codes please visit the Census site. 

Certain IMPLAN Sectors do not follow a normal NAICS pattern, including the construction Sectors, sector 361Imputed Rental Activity, and Sectors 427-440. For more information about these Sectors, please click here.