NAICS Classification Structure & Establishment-Level Assignment Overview
Overview of NAICS Classification
The North American Industry Classification System (NAICS) is a standard used by statistical agencies in the United States, Canada, and Mexico to classify business establishments according to the primary economic activity conducted at a physical location.
NAICS was introduced in 1997 as a successor to the Standard Industrial Classification (SIC) system and is revised periodically to reflect structural changes in the North American economy. The current edition is NAICS 2022.
Establishment-Level Classification Principle
NAICS assigns codes at the establishment level, not at the enterprise or corporate level. An establishment is generally defined as a single physical location where business is conducted or services are performed.
Each establishment is classified according to the primary activity taking place at that location. Primary activity is typically determined by the activity that generates the greatest share of revenue, value of production, or employment.
NAICS Hierarchical Structure
NAICS uses a hierarchical structure of two to six digits. Each additional digit increases classification specificity.
| Digit Level | Classification Level | Description |
|---|---|---|
| 2-digit | Sector | Broad economic category (e.g., Manufacturing, Construction). |
| 3-digit | Subsector | Subdivision of a sector representing related activities. |
| 4-digit | Industry Group | Cluster of closely related industries within a subsector. |
| 5-digit | NAICS Industry | Industry category generally comparable across the three NAICS countries. |
| 6-digit | National Industry | Most specific level of official NAICS classification within a country. |
Primary Activity Determination
When an establishment engages in multiple activities, classification is based on the activity that accounts for the largest share of revenue or production. Secondary activities are not used to determine the primary NAICS code unless they exceed the dominant activity.
This principle ensures consistent industry assignment for statistical reporting and economic analysis.
Revision Cycle
NAICS is reviewed and revised approximately every five years. Previous editions include:
- NAICS 1997
- NAICS 2002
- NAICS 2007
- NAICS 2012
- NAICS 2017
- NAICS 2022
Revisions may include industry splits, consolidations, title changes, or definitional clarifications. These updates are coordinated among statistical agencies of the United States, Canada, and Mexico.
Relationship to SIC
NAICS replaced the U.S. Standard Industrial Classification (SIC) system beginning in 1997 for most federal statistical purposes. SIC remains in use for certain regulatory and legacy reporting contexts.
Authoritative Sources
- Office of Management and Budget (OMB) — North American Industry Classification System, 2022 Revision (Federal Register Notice).
- U.S. Census Bureau — North American Industry Classification System (NAICS) Frequently Asked Questions.
- Statistics Canada — North American Industry Classification System (NAICS) 2022 Version 1.0.
- Instituto Nacional de Estadística y Geografía (INEGI) — Sistema de Clasificación Industrial de América del Norte 2022.