Electronic Catalog XML (eCX) is a data type definition (DTD) that provides a method for electronic catalog interoperability. It is unique because it deals with the difficult problem of dynamic categorization and attributes in electronic catalogs. It also provides a method to "inform" a catalog loading software of actions to take to update a catalog's structure and product information. eCX was developed in the fall of 1998 to address the problem of exchanging product information and catalog structure between different catalog systems. It was developed by Requisite Technology and is used by Requisite and its partners for catalog interoperability. eCX Web site Requisite.com

Counter for string and loop operations.

Concentration having an effect on x% of the population compared to control