This webpage is created to help researchers with product concordances of product classification codes in trade over time (CN8, HS6 and Prodcom codes).

We provide do-files that are easy to use and that can concord your product classifications over time to make sure that you can continue to track the same products over time even though its code changes over time.

A detailed description of the concordance issues can be found in the NBER paper below. If you use our do-files useful for your own research, please cite our NBER paper.

Van Beveren, Ilke, Andrew B. Bernard and Hylke Vandenbussche (2012)." Concording EU Trade and Production Data over Time". NBER Working Paper 8604.