What is the EIEM or BIEC?

An Enterprise Information Exchange Model (EIEM) is a MPD based on Business Information Exchange Components (BIEC). A BIEC is a NIEM-conforming XML schema data component (type, element, attribute, or other XML construct) that is reused, subsetted, and/or extended, that meets a business requirement for an information-sharing enterprise. An EIEM is a collection of BIECs organized into a subset and one or more extension schemas. Constraint schemas and non-NIEM-conforming external standards schemas with type adapters are optional in an EIEM.???????????

Links: http://reference.niem.gov/niem/guidance/business-information-exchange-components/1.0/