Boundary Expansion Review¶

A standing review — instantiates Migration-Resistant Hazard Control

Deliberately widens the evaluation boundary until it contains the whole system that generates and receives the hazard, so a control cannot score a win by pushing the hazard just past where anyone is counting.

Almost every control is judged inside the boundary of the unit that owns it — this plant, this quarter, this jurisdiction. Boundary Expansion Review is the periodic step that treats where that boundary is drawn as the thing under examination. It does not measure the hazard; it audits the frame around the measurement, asking whether the accounting line has been drawn narrower than the system that actually generates and receives the harm. Its single defining move is to challenge and redraw the boundary itself — not to detect displacement after the fact, but to make displacement impossible to hide by ensuring the destination sits inside the count from the start. A control that looks like a triumph inside a tight boundary and a wash inside a wide one has not reduced risk; it has relocated it, and this review is what forces that question before the win is banked.

Example¶

A national regulator celebrates that a heavy-industry sector cut its reported emissions by roughly a fifth over five years. A boundary expansion review widens the accounting frame from production inside the border to consumption by the economy, and imports the emissions embodied in goods now made abroad. Under the wider boundary the "reduction" mostly vanishes — output migrated to jurisdictions with weaker controls (classic carbon leakage), so the atmosphere saw little benefit. The review's product is not a new emissions number but a redrawn accounting boundary (consumption-based), an explicit tag on the national border as a risk-transfer boundary where hazard crosses out of view, and a boundary assumption log recording that the old assumption "domestic emissions ≈ total responsibility" was tested and rejected, with an owner and a re-review date attached.

How it works¶

Start from the current line and look outward. Take the boundary the control is scored inside and ask what it could be exporting across every edge — spatial, temporal, organizational, population.
Name the transfer edges. Enumerate the boundaries where hazard can cross out of the count; these become explicit risk-transfer boundaries rather than blind spots.
Widen until the source and all plausible destinations are inside. Expand the accounting boundary until the frame contains both what generates the pressure and everywhere it can land.
Log the frame, not just the result. Record each boundary assumption with an owner and an expiry, so the choice of frame is auditable and can be re-challenged next cycle.

Tuning parameters¶

Expansion aggressiveness — how far to widen: the adjacent unit, or the whole value chain. Wider catches more leakage but costs data and can dilute accountability until no one owns the number.
Boundary type under test — spatial, temporal, organizational, or population edges — which kind of transfer you go looking for. Different hazards escape along different edges.
Re-challenge cadence — a one-off reframing versus a standing review each planning cycle; how often the frame is allowed to ossify.
Assumption strictness — how much evidence a boundary assumption must carry before it is allowed to stand unchallenged.
Materiality floor — how large a cross-boundary transfer must be to force a redraw, versus being logged and tolerated.

When it helps, and when it misleads¶

Its strength is that it catches the single most common way displacement hides: a boundary quietly drawn to exclude the destination. It is the mechanism that keeps an evaluation honest about its own edges, and the carbon-accounting world's move from production- to consumption-based inventories is exactly this review at national scale.^[1]

It misleads in two directions. Widen forever and you reach analysis paralysis, or widen so far that accountability evaporates and no one is responsible for the whole. Its classic misuse is to run backwards — to draw the boundary to include a site where you already look good, or to exclude the place you are dumping to, manufacturing a win by choice of frame. The discipline that guards against this is to fix the boundary from the system's causal structure before the results are known, and to log every boundary assumption so a later reviewer can see the frame was chosen honestly rather than to flatter the answer.

How it implements the components¶

Boundary Expansion Review realizes the frame-setting side of the archetype — the components that decide what counts as inside, not what the hazard is doing:

accounting_boundary — its core output: the redrawn line defining what is inside the evaluation and therefore what a "reduction" has to hold true across.
risk_transfer_boundary — it names the edges where hazard can cross out of the accounting boundary, converting silent exits into declared crossing points.
boundary_assumption_log — it records each assumption behind the chosen frame, with an owner and an expiry, so the boundary can be re-litigated on evidence.

It does not model where the hazard actually travels (that's Intervention Displacement Stress Test and Whole-System Impact Map), nor keep the running tally of transferred hazard across those boundaries (that's Cross-Boundary Hazard Ledger). This review only fixes the line those mechanisms then work within.

Instantiates: Migration-Resistant Hazard Control — it supplies the honest boundary the rest of the appraisal is measured inside.
Consumes: a whole-system view (e.g., Whole-System Impact Map) to judge how far the boundary must widen.
Sibling mechanisms: Cross-Boundary Hazard Ledger · Cross-Jurisdiction Incident Review · Intervention Displacement Stress Test · Migration Sentinel Network · Pressure-Absorption Redesign Workshop · Source-Reduction or Safe-Dissipation Plan · Whole-System Impact Map · System-Wide Net-Risk Dashboard · Before–After–Elsewhere Evaluation · Adaptive Circumvention Red Team · Causal Loop Diagram · Agent-Based Experiment or Simulation · Fault Tree Analysis · Mass Balance · Hazard Analysis

Notes¶

The boundary this review fixes is the same boundary the Cross-Boundary Hazard Ledger reconciles across — the review chooses the line; the ledger keeps the books on it. Rerun the review whenever the system's reach changes (a new supplier, a new channel), or the ledger will faithfully balance the wrong frame.

References¶

[1] Carbon leakage — the effect whereby emissions curbed in one jurisdiction reappear in another as production relocates. It is the standard worked illustration of an accounting boundary drawn narrower than the system that generates the hazard, and of why widening the frame can erase an apparent reduction. ↩