Boundary Coherence Model (BCM): A Diagnostic Framework for Measuring Institutional Definitional Drift Institutions govern through operative definitions — terms that authorize coercive power, allocate resources, and constrain behavior. When these definitions drift from their original meanings without formal amendment, institutional coherence decays. No existing discipline provides quantitative instruments for detecting, measuring, or repairing this drift. The Boundary Coherence Model (BCM) fills this gap. The framework specifies six core metrics (λSD, λBD, λMM, H, RI, BDS), twenty-seven coded attributes with inter-rater reliability thresholds, eight failure gates with hard overrides, a four-instrument Intent Inference Protocol, and a five-layer continuous drift-detection architecture. Retroactive validation against the Late Roman Republic (133–27 BC) demonstrates that the BCM’s predicted collapse sequence — definitional drift → authority-liability decoupling → narrative-material divergence → semantic entropy saturation → reversion failure — matches the historically documented sequence of institutional failure at every phase. Prospective application to contemporary institutions (corporate, governmental, military) produces discriminant results across three orders of magnitude of institutional scale using identical instruments. The framework opens a new field — Institutional Coherence Analysis — at the intersection of political science, computational linguistics, psychometrics, information theory, causal time-series statistics, and formal logic. The BCM measures the distance between what institutions say and what they do. When that distance grows unchecked, institutions fail.
Thomas S. Hearl (Fri,) studied this question.