GCRI · Systemic Risk Management

Scenario design and stress testing

Scenario design and stress testing are the method this platform stewards for the network. They turn severe but plausible events into structured tests of plans, buffers and dependencies. In systemic risk management they are used to probe cross-sector cascades, to find breaking points and to compare preparedness across institutions on common assumptions.

01Register

Scenario design and stress testing on the record.

Method recordSTEM method
  1. MethodScenario design and stress testing
  2. StewardSystemic Risk Management
  3. Applied inSystemic Risk Management
  4. Canonical pageSTEM Commons
02Application

What scenario design and stress testing does here.

Scenario design and stress testing construct plausible, severe future conditions to examine how systems and institutions would perform. They complement probabilistic analysis where data are scarce or futures are deeply uncertain. In risk management and systemic risk and methods and modelling, stress tests reveal vulnerabilities that arise when several risks materialise together. They inform capital, contingency and coordination plans across sectors. The canonical description is on the STEM Commons.

Cross-sector scenario design

Scenarios are built with a trigger, severity, timing and conditions, then traced through the dependencies of energy, water, communications, finance and public services, with every assumption written down.

Reverse stress testing

Starting from a defined failure, such as a service stopping, analysts search for combinations of events that would cause it and document which ones are plausible.

Second-round effects

Tests add the reactions of institutions during a crisis, such as asset sales, supply hoarding or service cuts, to see how responses amplify or dampen the initial shock.

03Simulator

Stocks, flows, delays and a tipping threshold.

Two stocks, pressure and adaptive capacity, joined by a reinforcing growth loop, a delayed balancing response and damage when pressure outruns capacity; past the threshold the system can tip. Teaching model with stated illustrative values, not a prediction.

Controls

Growth of pressure
6.0% a year
Efficacy of capacity in reducing pressure
4.0% a year
Investment response to perceived pressure
20%
Perception delay
4.0 years
Tipping threshold of pressure
60 index
Amplification past the threshold
2.0 times
Years simulated
50 years

Readouts

Peak pressure
113 index
Capacity at the end
186 index
Years over the threshold
15.8 years
Numbers, methods and sources
YearPressureCapacityPerceived
020.050.020.0
423.344.921.2
827.242.224.0
1231.742.327.7
1636.845.532.2
2042.351.537.2
2447.960.342.6
2853.271.348.0
3257.884.353.1
3666.498.458.4
4082.7115.969.7
4497.8139.783.8
48109.1169.497.3

Methods

  1. System dynamics Forrester (1961), Industrial Dynamics, MIT Press; Sterman (2000), Business Dynamics
  2. Critical transitions and tipping points Scheffer and others (2009), Early-warning signals for critical transitions, Nature 461
  3. Causal loop diagram Sterman (2000), Business Dynamics, McGraw-Hill
  4. Uncertainty fan (parameter Monte Carlo) Spiegelhalter, Pearson and Short (2011), Visualising uncertainty about the future, Science 333
  5. One-at-a-time sensitivity (tornado) Saltelli and others (2008), Global Sensitivity Analysis: The Primer, Wiley

Data

No observed data enters this model: it runs on the teaching values set by the controls, to be replaced with a programme’s own evidence.

Stocks, flows, delays and a tipping threshold. Illustrative teaching model: it runs on the values set by the controls, not on measured data. Methods: System dynamics (Forrester (1961), Industrial Dynamics, MIT Press; Sterman (2000), Business Dynamics); Critical transitions and tipping points (Scheffer and others (2009), Early-warning signals for critical transitions, Nature 461); Causal loop diagram (Sterman (2000), Business Dynamics, McGraw-Hill).
04Data

What the method consumes.

Datasets and records used by scenario design and stress testing on this platform, with the role each plays and the label its values carry. Sources are listed in the source register.

DataRoleLabel
NGFS climate scenariosReference physical and transition pathwaysMODELLED
Reasonable worst-case planning scenariosCivil contingency assumptionsPublished statistics
Historical event reconstructionsCalibration of severityOBSERVED
Dependency inventoriesPropagation structureDECLARED
05Methods and evidence

How scenario design and stress testing is modelled, measured and tested.

The model, its assumptions, its data and its uncertainty, in the form a scientist or engineer would check. Structures follow published methods. The values drawn are illustrative, not findings.

Model, equations and assumptions

The model structure used for scenario design and stress testing, the assumptions it makes and how each is tested.

Risk of element iRi = f(Hi, Ei, Vi, Ci)hazard, exposure, vulnerability and coping capacity
Expected annual lossEAL = ∑k pk · Lkover events k with annual probability pk
Coupled systemsxt+1 = A xt + B ut + εtA carries the couplings, u the shock, ε the error
AssumptionWhy it is madeHow it is tested
Hazard and exposure are independent within an eventKeeps the loss integral tractableCompare with a copula fit on joint records
Couplings are linear near the operating pointLets shocks propagate through APerturb beyond the linear range and compare
Vulnerability curves transfer between placesLocal curves are rarely availableValidate against observed losses where they exist
Inputs
versioned datasets with provenance
Outputs
distributions, never single numbers
Code
released with the model card and tests
Reproduction
same data, code, environment and seed
Standard risk and state-space formulations; the assumptions listed are typical of the method, stated for review, not results.
FAIR guiding principles · GO FAIR and FORCE11W3C PROV · World Wide Web ConsortiumGuidance on consistent treatment of uncertainties · IPCCCEOS Analysis Ready Data · Committee on Earth Observation Satellites
06Validation

How results are checked.

Scenarios are reviewed for plausibility, internal consistency and severity relative to history. Exercise outcomes are compared with actual events when they occur.

CheckHow it is done
Plausibility reviewScenarios are reviewed by domain experts for internal consistency and plausibility before use
Severity benchmarkingScenario severity is compared with historical events and published reference scenarios
Model coverageThe share of mapped critical dependencies represented in the test is reported with the results

Scenario choice can reflect prevailing assumptions and miss novel combinations. Results depend on how participants and models represent responses.

08Stewardship

Who maintains the method.

Systemic Risk Management stewards scenario design and stress testing for the Consortium and reviews how it is applied across platforms.

09Questions

Questions and answers.

What are the limits of scenario design and stress testing in this field?
Scenario choice can reflect prevailing assumptions and miss novel combinations. Results depend on how participants and models represent responses.
How are results checked?
Scenarios are reviewed for plausibility, internal consistency and severity relative to history. Exercise outcomes are compared with actual events when they occur.
Are the values on this page real?
The data names, roles and checks are real descriptions of practice. The canvas shows a design of the method’s use, not a run; no result is reported here.
Where else is this method applied?
The canonical method page lists every platform that applies it.
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