The architecture team plays a key role in minimizing cost and streamlining Verification and Validation (V&V) starting with the thought of, “What are the system building blocks?”. During the system architecture definition phase, a functional analysis is necessary to visualize the types of system functional capabilities required to perform the desired operational needs. Identification of these functions can be derived from the system requirements or from determining the system’s information, material, and energy required for operations. An architecture team applies an Essential, Important, and Supporting (EIS) approach to “bin” the System functions and associated requirements using PTC Integrity Modeler ®. The EIS approach opened up a new verification method, “design-audit”, which was applied to system requirements to push normal rigor of verification to lower levels of architecture. In order for other programs to apply “design-audit”, a least resource intensive verification method, upfront in the architecture definition phase, this session covered “how” to identify system functions, “what” the EIS categories are, and “how” to get your customer and internal stakeholders on board.