Mineral Export & Rent Dependency Index — Methodology

Version 1.2 Last updated: July 2026

The Blomstra Mineral Export & Rent Dependency Index measures how economically exposed a country is to mineral extraction and exports. It is a structural indicator — it does not track real‑time prices or quarterly fluctuations, but rather identifies which economies are structurally dependent on minerals as a source of export revenue and national income.

1. Pillars

The index is composed of two equally weighted pillars. Both are required; a country missing either pillar is excluded from the ranking. No imputation or estimation is applied to missing data.

1.1 Ores & Metals Exports (% of merchandise exports)

• Indicator code: TX.VAL.MMTL.ZS.UN (World Bank WDI)
• What it measures: The share of a country’s total merchandise exports that consists of ores, metals, and minerals (excluding oil, gas, and agricultural products).
• Source: World Bank World Development Indicators, derived from UN Comtrade.
• Normalization ceiling: Clipped at 60% — any value above 60% is set to 60% (i.e., scores 100). This reflects the fact that once a country derives >60% of its exports from minerals, it is effectively maximally dependent for the purpose of this index.

1.2 Mineral Rents (% of GDP)

• Indicator code: NY.GDP.MINR.RT.ZS (World Bank WDI)
• What it measures: The share of gross domestic product (GDP) that comes directly from the extraction of mineral resources (coal, oil, gas, and metals).
• Source: World Bank WDI, derived from the World Bank’s Changing Wealth of Nations dataset.
• Normalization ceiling: Clipped at 15% — any value above 15% is set to 15% (i.e., scores 100). This reflects that very few countries derive more than 15% of GDP from mineral rents; those that do are already at the extreme of dependency.

Why these two pillars? Together they capture both the external (exports) and the internal (GDP) dimensions of mineral dependency. A country might have high export share but low GDP share if mining is capital‑intensive with little local value‑added; conversely, a country might have high rents but low export share if it is large and diversified (e.g., the United States). The composite gives a fuller picture.

2. Normalization & Scoring

Each pillar is converted to a 0–100 score using a simple linear transformation with pre‑set ceilings. This is not a statistical “min‑max” normalization across countries, but a judgment‑based ceiling that reflects what we consider “extreme” dependency.

Pillar	Raw range	Score formula	Ceiling (score 100)
Export share	0 – 60%	score = (value / 60) × 100	≥ 60% → 100
Mineral rents	0 – 15%	score = (value / 15) × 100	≥ 15% → 100

The final dependency score is the simple average of the two pillar scores, rounded to one decimal place:

Dependency Score = (Export_score + Rents_score) / 2

3. Staleness & Exclusion Rules

Data timeliness is critical. The World Bank’s mineral rents indicator (especially from Changing Wealth of Nations) is updated only every 2–4 years. To avoid ranking countries on decade‑old observations (e.g., New Caledonia’s export share from 2015 was previously inflating its score), we apply a hard staleness ceiling:

• Any observation older than 10 years from the current year is considered stale.
• If either pillar’s latest observation is stale, the country is excluded entirely.
• The excluded countries are listed separately with a clear reason.

Both pillars are required — if a country has data for one pillar but not the other, it is also excluded. No imputation or substitution is applied. This ensures that every country in the ranking is measured on a consistent, comparable basis.

The current staleness cutoff is 2016 (for 2026). As time passes, this cutoff automatically rolls forward. The data year for each pillar is shown on the dashboard next to the value, so users can always see the vintage of the underlying data.

4. Country Filtering

The World Bank’s indicator endpoints return both real countries and regional/income‑group aggregates (e.g., “Arab World”, “Caribbean small states”). We use the separate /v2/country metadata endpoint to filter out all non‑country aggregates, keeping only sovereign states and territories that have a valid region (i.e., region.id !== 'NA'). This ensures the ranking is limited to actual countries.

5. Interpretation

The dependency score is not a measure of “badness” — it is a measure of structural exposure. Higher scores indicate greater economic dependence on minerals, which can be both a blessing (export revenues, jobs) and a vulnerability (price volatility, Dutch disease, resource‑curse dynamics).

Suggested interpretation tiers:

• 0 – 25: Low mineral dependency — the economy is diversified.
• 26 – 50: Moderate dependency — minerals are a significant but not dominant sector.
• 51 – 75: High dependency — the economy is substantially reliant on minerals.
• 76 – 100: Extreme dependency — the economy is heavily exposed to mineral markets.

For example, the Democratic Republic of Congo (score 100) derives over 75% of its exports from ores and metals and nearly 30% of its GDP from mineral rents. This makes it extremely vulnerable to cobalt/copper price shocks. In contrast, Germany (score ~8) has negligible mineral dependency.

6. Limitations

• Commodity‑level concentration is not captured: This index measures overall mineral dependency, not the concentration of specific commodities (e.g., rare earths, cobalt, lithium). That is a separate, more granular analysis that we plan to cover in a future Supply Concentration Index.
• Data lags: Mineral rents data (Changing Wealth of Nations) is updated irregularly, with a typical lag of 2–4 years. The staleness ceiling mitigates this, but users should always check the data year.
• No quality adjustment: The index does not account for governance, infrastructure, or the quality of mineral‑sector regulation. It is purely a dependency metric.

7. Updates & Schedule

The index is rebuilt weekly but the underlying WDI data is updated by the World Bank on a rolling basis. When new data is published for a country, the next weekly refresh will incorporate it. The staleness cutoff is evaluated at build time.

8. References & Data Sources

• World Bank World Development Indicators (WDI)
• UN Comtrade – underlying trade data for export share indicator
• World Bank Changing Wealth of Nations – underlying data for mineral rents

9. Credits

The Blomstra Mineral Export & Rent Dependency Index is produced by Blomstra Insights, a strategic intelligence platform. The methodology was developed by the Blomstra research team and is openly published to promote transparency and reproducibility.