GCRI · Trade and Strategic Resources
Methods and uncertainty
The methods Trade and Strategic Resources relies on: their equations and assumptions, the data they need, how they are validated and the limits of what they can show.
The workspace for methods and uncertainty.
Evidence register
Trade and resources · Methods and uncertainty · Example interface, not a record
Indicators
unit · cadence · label
| Transit time | days | weekly | OBSERVED | SP-4434 |
| Supplier concentration (HHI) | index | quarterly | DERIVED | SP-2755 |
| Inventory cover | days | weekly | REPORTED | SP-9473 |
| Freight rate index | index | weekly | OBSERVED | SP-7356 |
| Share of supply from top source | of volume | quarterly | DERIVED | SP-8892 |
Source passport
- Source
- Customs trade flows
- Licence
- open · attribution
- Steward
- Port authority
- Coverage
- 72 pct of places
- Known limits
- sparse in uplands
Coverage by place
Trade and Strategic Resources · Evidence register. Evidence register: example names and illustrative values, not a record.
The methods in use.
- 01Network science and contagionTrade network centrality · Multi-tier dependency mapping · Disruption propagationApplied here
- 02Optimisation and operations researchRerouting under chokepoint closure · Strategic stock sizing · Sourcing portfolio designApplied here
- 03EconometricsPrice transmission · Effects of trade measures · Disruption impacts on outputApplied here
- 04Geospatial information systemsFacility hazard overlays · Sourcing region deforestation · Corridor mappingApplied here
- 05Materials science and chemistryProcessing route analysis · Recycling potential · Substitution optionsApplied here
- 06Urban and transport engineeringPort capacity and congestion · Freight corridor resilience · Hinterland connectionsApplied here
Each method, its role in this field and how it is checked.
- Network scienceRole hereNetwork science represents trade and supply as networks of countries, firms and routes.Checks appliedRe-export correction; Sensitivity to substitution; Event validation
- OptimisationRole hereOptimisation and operations research decide how to route, stock and diversify supply under cost and risk.Checks appliedOut-of-sample scenarios; Operator review; Trade-off reporting
- EconometricsRole hereEconometrics estimates relationships in trade and price data from observed history.Checks appliedPre-trend tests; Robustness to specification; Structural break tests
- GeospatialRole hereGeospatial information systems locate mines, fabs, ports, routes and producing regions, and overlay them with hazards, conflict and environmental data.Checks appliedLocation verification; Hazard map resolution; Attribution uncertainty
- Materials chemistryRole hereMaterials science and chemistry explain which materials a technology needs, how they are refined, and which can be recycled or substituted.Checks appliedMass balance; Technology readiness; Expert review
- Urban transport engineeringRole hereTransport engineering designs and operates the ports, terminals, corridors and freight networks that carry trade.Checks appliedCapacity validation; Model calibration; Hazard exposure review
How the process runs.
Process explorer · Process
Methods and uncertainty: PRISMA 2020 review reporting
10 steps·4 stages
Process
Methods and uncertainty: PRISMA 2020 review reporting
PRISMA 2020 is a reporting guideline for systematic reviews; the steps follow its checklist, not a mandated sequence, and no Nexus document adopts it.
01 Plan
- 01Registration and protocolRecord · The review teamThe guideline asks for registration details, access to the protocol and any amendments.
- 02Eligibility criteriaRecord · The review teamThe guideline asks for the inclusion and exclusion criteria and how studies were grouped.
02 Find and select
- 03Search: sources and strategiesStep · The review teamThe guideline asks for the information sources and the full search strategies. It does not fix which sources are used.
- 04Selection of studiesStep · The review teamThe guideline asks how studies were judged eligible, including how many reviewers screened. It does not fix the number of reviewers.
- 05Flow diagramRecordThe flow diagram shows the number of records found, the number of studies included and the reasons for exclusion.
03 Analyse
- 06Data collectionStep · The review teamThe guideline asks how data were collected from reports and which data items were sought.
- 07Risk of biasStep · The review teamThe guideline asks for the methods and tools used to assess risk of bias.
- 08SynthesisModel · The review teamThe guideline asks for the effect measures and the synthesis methods. It does not prescribe meta-analysis.
- 09Certainty of evidenceStep · The review teamThe guideline asks for the methods used to assess certainty, and reports the result per outcome. It does not name a grading scale.
04 Report
- 10Review reportRecordThe guideline helps authors report why the review was done, what they did and what they found.
ReportsOutline of an externally published reporting guideline, not a Nexus process and not a record of operation. PRISMA 2020 mainly covers reviews of intervention effects. No Nexus page names it. Every programme is at service level R0.
Where uncertainty in supply chain analysis comes from, and how it is shown.
| Source | Why it matters here | How it is reported |
|---|---|---|
| Firm-level links | Customs data stop at the border; tiers below are invisible | Concentration at product level; firm links labelled when inferred |
| Inventories | Buffer stocks are rarely disclosed | Scenario ranges |
| Substitution | Elasticities for critical inputs are poorly known | Sensitivity analysis |
| Policy | Export measures can change overnight | Policy scenarios |
Concentration indices are reported by stage of the chain and by measure (volume, value).
How uncertainty is reported.
- 01
State assumptions
Each analysis lists its assumptions and the data it depends on.
- 02
Quantify where possible
Ranges and confidence are reported alongside central estimates.
- 03
Validate and compare
Models are checked against observations and, where possible, against other models.
- 04
Publish limits
What an analysis cannot show is stated beside what it can.
Where this page’s references lead.
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
Questions and answers.
Are the methods open?
Contribute evidence from this page.
Reports is the Consortium’s quarterly publication. What you know about this subject can become evidence, a case or a correction in the next edition, credited to you and published under CC BY 4.0 where it is your own work.
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