G-P01 · TOPIC · quantitative-and-qualitativeGCRI dossier · service level R0
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Topic dossier · Systemic Risk Management

Quantitative and qualitative methods

Risk assessment uses numbers where data support them and structured judgement where they do not. Probabilistic models, loss distributions, expert elicitation, bow-tie diagrams and risk matrices each answer different questions and fail in different ways. This page sets out how the main methods work, when each is fit for purpose, and how combining them keeps an assessment honest about what is known and what is assumed.

01In brief

The short answer.

Risk assessment methods are the techniques used to identify, analyse and evaluate risk, from probabilistic models and loss distributions to expert elicitation, bow-tie diagrams and risk matrices. Each answers different questions and fails differently. Combining them, and recording data, assumptions and ranges, keeps an assessment honest about what is known.

02Geography

Hazards and exposure in Asia.

For quantitative and qualitative methods, in GCRI's spatial-intelligence reading, the map opens on true-colour imagery, land cover and night lights, framed on Asia; every other NASA layer, live feed and forecast waits in the layer list.

The interactive map needs JavaScript; the layer list and sources are below.

Layers 3

Hazards and exposure, for this page

Latest available

NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth

Loading the latest NASA imagery.

Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.

For quantitative and qualitative methods, in GCRI's spatial-intelligence reading, the map opens on true-colour imagery, land cover and night lights, framed on Asia; every other NASA layer, live feed and forecast waits in the layer list.Satellite and model products as NASA publishes them, each with its own date; indicators, not assessments of any place; claim ceiling INTEGRATED.

Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · NASA EONET · GDACS · Copernicus Sentinel-2 L2ASources and licences

  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • VIIRS Black Marble night-time lights, NASA Goddard Space Flight Center; distributed by the NASA Level-1 and Atmosphere Archive and Distribution System (LAADS DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). CC BY 4.0
  • NASA Fire Information for Resource Management System (FIRMS), VIIRS 375 m active fire product, NASA LANCE; vector tiles via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
  • © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). ODbL
  • Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
  • Globe: MapLibre GL JS 6.9.1, BSD-3-Clause, © MapLibre contributors.
  • Live: NASA EONET Events are indicative, not official warnings.
  • Live: GDACS (EC JRC / UN OCHA) Events are indicative, not official warnings.
  • Observed (EO): Copernicus Sentinel-2 L2A (contains modified Copernicus Sentinel data 2026), Microsoft Planetary Computer
  • Optional layers (35 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.

Layers and dates

  • True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
  • Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
  • Night-time lights, daily: VIIRS Black Marble (VNP46A2), NASA LAADS DAAC · 12 Oct 2026
  • Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
  • Flood water, 3-day composite: VIIRS Global Flood Product, NASA LANCE · 14 Oct 2026
  • Active fires and thermal anomalies, last day: VIIRS NOAA-20 375 m (FIRMS), NASA LANCE FIRMS · 13 Oct 2026

03Console

Cascade and stress lab, in outline.

The working screen behind this subject: its structure, terms and states. Names are placeholders and values illustrative.

Cascade and stress lab

Quantitative and qualitative methods · National system · Scenario SC-40

Cascade crosses three systemsGCRI · Systemic Risk Management

Interdependency graph

red: failed in scenario

Cascade sequence

  1. T+0HAZHeatwave and drought
  2. T+6hENGThermal plant derated, cooling water
  3. T+9hICTData centre on backup power
  4. T+14hWATPumping reduced, pressure loss
  5. T+20hHLTHospital water supply at risk

Service loss by system

Cascade and stress lab: the screen's structure, terms and states for Quantitative and qualitative methods.Placeholder names and illustrative values; a design, not a record or a live system.
04The question

Quantitative and qualitative methods: how the risk develops.

Probability, uncertainty and judgment. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.

Mechanism

Models need data that fit

Frequency and severity models work where events are numerous and recorded consistently. For rare, novel or changing risks the data are thin, and a precise-looking number can carry more assumption than evidence.

Mechanism

Judgement carries biases

Experts anchor on recent events, overestimate their own precision and converge in groups. Structured elicitation reduces these effects by separating estimates, asking for ranges and scoring calibration.

Mechanism

Matrices compress information

Likelihood and consequence matrices are quick to use, but they rank risks coarsely, can reverse orderings and hide correlated losses. They suit screening, and need other methods before a major decision.

Mechanism

Methods combine through structure

Fault trees, event trees and bow-tie diagrams link causes, controls and consequences. They provide a frame into which quantitative estimates and expert judgement can be placed and checked.

05Key terms

Terms used on this page.

Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.

TermDefinition
Risk matrixA grid that ranks risks by combining likelihood and consequence categories, useful for screening.
Bow-tie analysisA diagram linking the causes of an event, the controls that prevent it, and the consequences and controls that limit them.
Structured expert judgementA formal elicitation method that scores experts on calibration questions and combines their estimates accordingly.
06Indicators

What is measured, and how well.

Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.

IndicatorUnitCadenceSource typeLabel
Risks assessed with quantitative estimatespercent of principal risksannualAssessment recordsREPORTED
Calibration of expert estimatescalibration score on seed questionsper elicitationStructured expert judgement recordsOBSERVED
Loss event recordscount of events with cause and amount recordedcontinuousInternal loss databasesOBSERVED
Assessment uncertainty rangeratio of upper to lower boundper assessmentAssessment outputsESTIMATED
Controls with tested effectivenesspercent of key controlsannualControl testing recordsREPORTED
Method documentation completenesspercent of assessments with method, data and assumptions recordedannualAssessment filesREPORTED
07Canvas

From sources to decisions.

The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.

Pipeline canvas · Quantitative and qualitative methods as a run graphDesign, not a record
Quantitative and qualitative methods: a cascade across interdependent systemsA hazard hits one system; dependencies carry the failure into others; impact grows until buffers, redundancy or restoration priorities stop it; the analysis ranks the links to strengthen. Design of the process, not a record of a run.

Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.

08Sources

Where the evidence comes from.

Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.

SourceWhat it givesLicence class
IEC 31010 Risk assessment techniquesDescriptions, strengths and limits of more than forty techniquesLicensed standard, purchase required
EM-DAT international disaster database (CRED, UCLouvain)Disaster events with human and economic impactsFree for non-commercial use with registration
Sendai Framework Monitor and national disaster loss databasesOfficial reporting of disaster losses against Sendai targetsPublic, UN terms of use
TU Delft expert judgement databasePast structured expert judgement studies with calibration dataLicence to check
Published operational loss data consortia summariesAggregate operational loss patterns in financial servicesMembers only; public summaries (to check)
09Decisions

Who decides, and what the evidence serves.

Systemic Risk Management prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.

Who decidesThe questionEvidence this page serves
Risk functions and analystsWhich method fits a given risk and decisionMethod selection guides; documentation standards
Boards and executivesHow much confidence to place in an assessment before acting on itUncertainty ranges; method documentation; calibration records
Regulators and supervisorsWhether an institution's risk models are fit for the use made of themModel documentation; validation and back-testing evidence

Outputs this topic produces

  • Method selection guides keyed to the question and the evidence available
  • Structured expert elicitation protocols with calibration
  • Bow-tie and fault-tree templates linked to registers
  • Assessment files that record data, assumptions and ranges
10Core questions

What methods experts ask.

  • Is there enough relevant data to estimate probabilities, or would numbers convey a false sense of precision?
  • What kind of uncertainty dominates: randomness, lack of knowledge, or disagreement about how the system works?
  • How sensitive is the decision to the parts of the analysis that are least certain?
  • How can expert judgement be elicited so that it is transparent and less prone to bias?
11Mechanisms

Kinds of uncertainty.

Aleatory

Randomness

Natural variability that persists even with perfect knowledge, such as weather from year to year. Probability handles it well.

Epistemic

Lack of knowledge

Uncertainty that more data or research could reduce. It should be shown, not hidden in a single number.

Deep

Disputed structure

Where experts disagree on models, probabilities or values. Scenarios and robust decision methods suit it better.

12Methods and limits

A toolkit, matched to the problem.

  1. 01

    Statistical and probabilistic models

    Frequency analysis, extreme value methods and Bayesian inference from probability and statistics. Limits: rare events are poorly sampled, and past data may not reflect a changing system.

  2. 02

    Uncertainty quantification

    Uncertainty quantification and model validation propagates input uncertainty through models and tests them against data. Limits: it cannot capture what the model leaves out.

  3. 03

    Structured expert judgement

    Formal elicitation protocols that calibrate and combine expert views. Limits: time-consuming, and experts share blind spots.

  4. 04

    Qualitative assessment

    Scales, matrices and narrative analysis. Useful for communication and screening, but risk matrices can rank risks inconsistently and should not be the only tool.

13Methods

How it is studied, and what the methods cannot say.

  1. Probability and statisticsFrequency and severity modelling · Dependence between risks · Combining data and judgementApplied here
  2. Uncertainty quantification and model validationPropagating input uncertainty · Separating kinds of uncertainty · Deep uncertainty framingApplied here
  3. Decision analysis under uncertaintyMulti-criteria treatment choice · Decision trees for contingent plansApplied here
  4. Scenario design and stress testingCross-sector scenario design · Reverse stress testing · Second-round effectsApplied here
14Questions

Questions and answers.

Are risk matrices reliable?
They are useful for screening and communication, but they rank risks coarsely and can mislead when risks are correlated or consequences are uncertain. Important decisions need methods that show ranges and dependencies.
What is structured expert judgement?
A formal process for eliciting estimates from experts, often with seed questions whose answers are known, so that each expert's calibration and informativeness can be scored and estimates combined accordingly.
When should risk be quantified?
When data or models can support a number whose uncertainty can be stated, and when the decision needs it. Where they cannot, a well-documented qualitative assessment is more honest than a false number.
Are quantitative methods always better?
No. They are better when data and models are adequate. Where they are not, numbers can mislead, and structured qualitative methods or scenarios are more honest.
What is wrong with risk matrices?
They are simple and widely understood, but coarse scales can rank different risks equally, hide uncertainty and ignore dependence. They work best as a screening tool alongside other methods.
How should uncertainty be communicated?
With ranges, scenarios and plain statements of what is not known, so that decision-makers can see how much the conclusion depends on uncertain inputs.
Systemic Risk Management

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