The North American Industrial Classification System (NAICS) is a set of codes that allows you to find more information on market size and industry ratios, build a list of competitors, and more. NAICS is the standard used by Federal statistical agencies.
Please visit the US Census Business and Industry website for reports that measure various industries using the NAICS. You can gather the following type of information on this website.
Finding Industry Codes Video Tutorial: This video describes how to locate SIC and NAICS codes for business research. Created by Amanda Howell, Reference & Instruction Librarian at UW-Whitewater.