The Architecture Ledger: A Measurement Practice for Cost, Risk and Flexibility on a Mined Dependency Graph

Abstract

Version 1.1d. A standing measurement practice attaching three distributional quantities to each use case within a named business subdomain, over a mined dependency graph: metered unit cost as a coefficient of business volume, monetary risk as loss distributions, and a flexibility term. This version narrows two published claims rather than adding capability. Earlier versions held that declared subdomain boundaries determine where cost pools are cut, where risk propagation is bounded, and where option value is located. Executed against the framework's own worked allocation basis, the cost axis is invariant to the declared partition to machine precision, and the option-value clause is untested. Only the risk clause survives (R24). Separately, the fixed-cost allocation basis was used in the cost identity and defined nowhere; it is now specified at Part IX 9.2.8, which mandates partition-independent bases and prohibits two-stage allocation (R23). No formula changes in any document. Three arithmetic corrections at Part IX 9.10 were independently re-derived and verified, including a closed-form derivation of the Datar-Mathews block agreeing with simulation to within 0.01 percent. Title changed from Enterprise Architecture Economics at v1.1; "economics" named a discipline that does not exist. This version includes a full disclosure of the AI assistance used in the research and drafting. Independent research conducted in a personal capacity. Vendor-neutral, and unconnected to the author's employer.