PLACE OF THIS DOCUMENT IN THE VIEN GUT DOSSIER

Document A.2 is not a procedural document, not a document applied to a single disease axis, and not a document intended to prove the international evidence base of the HOW gap. A.2 is the foundational definition document. If A.1 showed that the modern EBM chain encounters a structural break at the stage of clinical application for patients with complex chronic multimorbidity, then A.2 answers the next question: what exactly are the three layers the Vien Gut Model uses to fill that gap — WHAT, HOW, and DATA-to-operate; where are their boundaries; what do they contain; and why can they not substitute for one another.

Within the four-tier architecture of the dossier, A.2 belongs to Tier 1 — Basic Architecture. It sits between A.1 and A.3, serving as an academic bridge: A.1 identifies the break in the EBM chain; A.2 defines the three layers that fill the gap; A.3 confirms that gap through international evidence; and A.4–A.5 elaborate the operational terminology in detail. At the same time, A.2 is the foundational document for reading the whole of Section B and Section C — where these three layers are operationalized into care processes and verification targets.

ABSTRACT

Document A.2 has one single purpose: to identify and define precisely the three architectural layers of the Vien Gut Model — WHAT, HOW, and DATA-to-operate — before the reader proceeds to Section B and Section C. Readers, especially international reviewers unfamiliar with this framework, need to understand what these three layers are, where their boundaries lie, what they contain, and why they do not compensate for one another. A.1 presented the EBM framework and identified the structural break when applied to complex chronic multimorbidity; A.2 answers the next question: what exactly are the three layers that the Vien Gut Model constructs to fill that gap? A.4 will then elaborate each specific operational term in detail.