In the context of an economic integration agreement (EIA), the issuing and verification of certificates of origin are carried out in accordance with procedures which ensure compliance with the rules of origin. Each EIA has its own system of rules of origin with their corresponding procedures. The purpose of the rules is to define clearly the geographical provenance of a good which may benefit from preferential tariffs in the importing country. The main purpose of the rules of origin is to avoid the diversion of trade, so that preferential tariff treatment is applied only to those products negotiated between the parties. The rules of origin of an EIA are more important than the actual process of tariff reduction, as that process is concluded at some point in time, whereas the rules of origin remain applicable indefinitely.