Are you a business or economics student or researcher? Then you'll have an idea of what SIC & NAICS are, they're classification systems for organizing business statistics. Many business books and sites present their statistics organized by these systems. The SIC is the older system, the NAICS the newer one. Some sites and books use both, like our online Business and Company Resource Center. Other resources use one, some the other, so how do you go back and forth, how to compare?
One was is to go to page 307 in our new copy of Business Statistics of the United States. It's a print book in our reference collection, REF HC101 .A13122. There you will find a page that gives an overview of the two systems, and then there are some pages following that show you how the NAICS was derived from the older SIC.