As systems continue to increase in both size and complexity, the ability to drill down and find the failure root causes continues to be a growing challenge. Many of the traditional methods to compute low-level reliability or maintainability statistics in complex designs and bring this data to the system level to address system requirements conformance is becoming increasingly costly and challenging.

The eXpress Diagnostics Model is effective for all levels of the design architecture and can be expanded or enriched to facilitate the Diagnostic Design or the Sustainment objectives at any time.
The approach for initiating towards the goal of achieving diagnostic effectiveness for any design begins with identifying where we are in the design development or design support lifecycles, while also considering the diagnostic or sustainment requirements or objectives. The eXpress model captures and extends diagnostic expertise regardless of where we are in the design or sustainment lifecycles and for any sustainment implementation.