In 2006, the six Regional Entities within the Eastern Interconnection developed and executed an agreement that governs the inter-regional transmission reliability assessment studies within the Eastern Interconnection. That agreement established an Eastern Interconnection Reliability Assessment Group (ERAG) Management Committee (MC) that oversees all of the inter-regional study activities. In late 2006, the North American Electric Reliability Corporation (NERC) Planning Committee (PC) transferred oversight of the Multiregional Modeling Working Group (MMWG) to ERAG. The MMWG has responsibility for developing all Eastern Interconnection power flow and dynamic base case models, including seasonal updates to summer and winter power flow study cases.

In 2016, the six Regional Entity President & CEOs within the Eastern Interconnection executed a revised Agreement to include development of power flow and dynamic transmission system models and review of Planning Coordinator reliability assessments. ERAG’s mission is "to preserve and enhance the bulk power system reliability of the Eastern Interconnection." In doing so, ERAG is committed to supporting the efforts of and serving as an extension of NERC in its mission as the Electric Reliability Organization (ERO) to ensure the reliability of the bulk power system within North America. ERAG’s vision is "to be recognized as the trusted and credible technical resource that leads the independent analysis, assessment, and enhancement of bulk power system reliability for the Eastern Interconnection. 　

The new Agreement contains main functions:

1. Perform reliability assessments of the Eastern Interconnection to identify potential reliability issues and risks supplemented by the review of appropriate reliability assessments prepared by Eastern Interconnection Reliability Coordinators and Planning Coordinators;

2. Fulfill obligations under their Eastern Interconnection Base-case Model Creator and Interim-Designee Agreement with NERC; Fulfill obligations under their Eastern Interconnection Base-case Model Creator and Interim-Designee Agreement with NERC;

3. Address agreed upon steps developed under their Eastern Interconnection Events Analysis Model Building Plan Agreement The ERAG is populated by two representatives from each its members as well as a liaison from NERC.

The ERAG will carry out the intent of the agreement by performing various studies, reviewing pertinent documents produced by the EI Planning Coordinators, managing the MMWG; and by engaging in other activities which in the collective opinion of the members of the ERAG would be consistent with the intent of the above-mentioned agreement.

The ERAG activities and studies are also governed by the NERC Rules of Procedure and Regional Delegation Agreements.