Model Breakdown

Definition:
The decision model becomes invalid due to changes in external conditions.

Signal:
Predictions consistently fail despite correct execution.

Rule:
If the model fails → discard and rebuild.

Test:
If external conditions change AND model predictions consistently fail → this is Model Breakdown.

Entries

Key Difference:
Model Breakdown is driven by external change, while Strategy Drift is internal deviation.

Boundary:
External disruption → Model Breakdown.
Internal misalignment → Execution Drift.

This crux belongs to:

→ The Decision Ledger