Methodology
The Evacuation Inform Index (EII) is structured as a ratio β the Risk Score for Evacuating (RSE) divided by the Risk Score for Staying (RSS) β synthesising the INFORM Severity 3-dimension structure with the IOM RICD macro/micro split.
Three-layer architecture
| Layer | Function | Precedent |
|---|---|---|
| Layer 1 β Objective Risk Score (ORS) 50% | Universal factors, identical for everyone in the geography (hostilities, conflict risk, natural-hazard life risk) | INFORM Severity, ACLED, GCRI |
| Layer 2 β Infrastructure & Access (IAS) 35% | Availability of evacuation routes, resources & connectivity | ACAPS Humanitarian Access, IDMC |
| Layer 3 β Personal Vulnerability Modifier (PVM) 15% | Demographic / household factors applied as a multiplicative modifier (0.7Γβ1.3Γ) | CDC SVI, IOM RICD micro-level |
Aggregation β weighted geometric mean
Indicators aggregate by weighted geometric mean rather than arithmetic mean, so an extreme imbalance (e.g. all infrastructure unavailable) cannot be compensated by a low score elsewhere β the same logic used by the Human Development Index and INFORM Risk.
Recommended build sequence
| Phase | Method | Purpose |
|---|---|---|
| 1 Β· Variable design | Delphi + Budget Allocation (8β12 experts, 2 rounds) | Set initial layer & sub-variable weights |
| 2 Β· Weight validation | Fuzzy AHP (triangular numbers, Buckley's geometric mean) | Validate contested weights under uncertainty |
| 3 Β· Calibration | Historical case testing (Sudan '23, Ukraine '22, Kabul '21, Lebanon '06, Haiti '10) + PCA | Check the index matches real decisions; prune redundant variables |
Constraint layers (not scored)
Financial feasibility filter β a second-stage check on whether the recommended action is affordable (transport, accommodation, asset-liquidation loss, income disruption). Legal / rights (UDHR Art. 13) β flags exit-visa requirements, travel bans or closure orders that restrict self-evacuation.
Variables & Proposed Weights
Preliminary weights synthesised from INFORM, ACLED and FSI logic β to be validated by AHP expert surveys.
Layer 1 β Objective Risk Score Β· 50%
| Variable | Data source | Weight | Rationale |
|---|---|---|---|
| Active hostilities | ACLED: fatalities, attack types, proximity | 20% | Immediate life threat; fastest-changing β heaviest weight |
| Likelihood of future hostility | GCRI risk score; FSI security; ICEWS | 15% | Forward-looking; less certain than observed events |
| Life risk (non-conflict) | IDMC, FEWS NET β flood, quake, fire | 15% | Natural-hazard exposure alongside conflict |
Layer 2 β Infrastructure & Access Β· 35%
| Variable | Data source | Weight | Rationale |
|---|---|---|---|
| Evacuation route availability | Flight seats, road/border status, satellite imagery | 12% | No route = evacuation impossible |
| Infrastructure availability (stay) | Internet, energy, food, water (IPC, FEWS NET) | 10% | Determines survivability if staying |
| Security / threat alerts | OSAC, embassy alerts, local-language news | 8% | Near-real-time signal, both directions |
| Weather | NOAA, Copernicus | 5% | Modifier on route viability & shelter |
Layer 3 β Personal Vulnerability Modifier Β· 15% (multiplicative 0.7Γβ1.3Γ)
| Variable | Operationalisation | Direction of effect |
|---|---|---|
| Young children (<12) | CDC SVI "age β€17"; self-report | β RSE (harder to move) & β RSS (more vulnerable) |
| Elderly (65+) | CDC SVI "age 65+"; self-report | β RSE (mobility) & β RSS (medical risk) |
| Gender / gendered risk | UNHCR GBV risk indicators | β RSS in conflict zones with GBV risk |
| Prior evacuation experience | Self-assessed preparedness | β RSE (more capable evacuee) |
| Financial resources | Self-reported | β RSE when high; β RSS when low |
Weighting methods considered
| Method | Subjectivity | Data | Defensibility | Use |
|---|---|---|---|---|
| Equal weights | None | None | Low | Baseline & sensitivity |
| Budget allocation (BAP) | High | None | Medium | Rapid prototyping |
| AHP | Medium | Expert survey | High | Published index |
| Fuzzy AHP | LowβMed | Expert survey | Very high | Ambiguous variables |
| PCA / factor analysis | None | Historical | Medium | Validation & pruning |
Data Sources
Feeds that populate the index. All free unless noted.
Reference Indices & Key Papers
Methodological precedents
INFORM Severity Index
3 weighted dimensions (Impact 20% Β· Conditions 50% Β· Complexity 30%), 1β5 scale. Closest analogue.
acaps.org βACLED Conflict Index
Deadliness 35 Β· Danger to civilians 25 Β· Diffusion 20 Β· Fragmentation 20; non-linear root aggregation.
acleddata.com βIOM RICD
Two-tier macro (spatial risk) + micro (community) model β the structural precedent for base score Γ personal modifier.
iom.int βIDMC Risk Model 2.0
Probabilistic displacement from natural hazards β feeds the "risk of staying" dimension.
internal-displacement.org βFragile States Index
12 indicators, CAST text-analysis triangulation β template for structural / minor variables.
fragilestatesindex.org βCDC Social Vulnerability Index
16 variables, 4 equally-weighted themes, percentile ranking β the personal-vulnerability layer.
atsdr.cdc.gov βGlobal Conflict Risk Index
Conflict-onset risk β separates active conflict (ACLED) from forward-looking risk.
jrc.ec.europa.eu βOECD/JRC Composite Handbook
Definitive reference for normalisation, aggregation, weighting & sensitivity analysis.
publications.jrc.ec.europa.eu βKey papers
- Beccari, B. (2016). A Comparative Analysis of Disaster Risk, Vulnerability and Resilience Composite Indicators. PLoS Currents Disasters, PMC4807925 β reviews 106 index methodologies.
- Can severity of a humanitarian crisis be quantified? Assessment of the INFORM severity index. Globalization & Health (2023). DOI:10.1186/s12992-023-00907-y β identifies governance & access as strongest predictors.
- Al Fozaie (2022). A Guide to Integrating Expert Opinion and Fuzzy AHP When Generating Weights for Composite Indices. Advances in Fuzzy Systems. DOI:10.1155/2022/3396862.
- OECD/JRC (2008). Handbook on Constructing Composite Indicators. OECD Publishing.
- Saaty, T.L. (1990). How to Make a Decision: The Analytic Hierarchy Process. EJOR 48(1), 9β26.
- ACAPS Ukraine Severity Model Methodology Note (March 2024) β worked subnational example.