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NationsTree / Methodology

Methodology

Every shape of every tree and every index score is calculated from published statistics with one public set of rules, the same for all countries. Index version v0.9.

1. Data

Values come from official statistics: mainly the World Bank World Development Indicators and Worldwide Governance Indicators, which compile data from UN agencies (UN Population Division, UNESCO, WHO, UNICEF, ILO, UN Tourism), the IMF, SIPRI, national statistical offices and other bodies. Country identifiers, capitals, flags and founding years come from Wikidata.

  • Every value is stored with its year, source series code and download date. Raw responses from each source are archived on our servers, so the database does not depend on future availability of external services.
  • Data are refreshed automatically every week; the date shown as “data as of” is the last successful refresh.
  • Where a value for a year is missing, the latest earlier value is used for up to 5 years and is always shown with its own year. Older values are not used for the index.
  • World rank: position among countries reporting the indicator. For the “latest available” view, only countries with data from the last 5 years of the series are ranked. For indicators where less is better (e.g. inflation, homicide rate), 1st is the lowest value.

2. NationsTree Index

Each indicator is converted to a percentile among countries with data in that year (0 = lowest, 100 = highest; reversed where less is better; inflation is measured as distance from 2%). A pillar is the average of its available components (at least half of them). The index is the weighted average of the pillars; a country needs at least 4 of 5 pillars.

PillarWeightTree partComponents
Foundations25%RootsCompleted lower secondary, 25+ · Secondary enrolment · Tertiary enrolment · Physicians · DPT immunization · Safely managed drinking water · Access to electricity · Internet users · Government effectiveness · Rule of law
Strength20%TrunkGDP (PPP) · Population · Exports of goods & services · Scientific articles · Patent applications by residents · R&D spending
Quality25%Crown density and colourLife expectancy · GDP per person (PPP) · Under-5 mortality · Safely managed sanitation · Extreme poverty · Social protection coverage (incl. pensions)
Problems20%Dry branches, brown and falling leavesHomicide rate · Control of corruption · Political stability · Inflation · Unemployment · Air pollution (PM2.5) · Extreme poverty
Direction10%New shootsPercentile of the 5-year change of the average of the other four pillars

3. How a tree is drawn

Height (scale about 1:100 between the largest and smallest)

H = 0.8 × √(real GDP, PPP, constant 2021 prices, bn USD) × (0.6 + 0.4 × index / 100)   [metres]
above 150 m:  H' = 150 + 50 × (1 − e^(−(H − 150) / 50))   → never above 200 m

Real (inflation-adjusted) GDP means a tree grows only when the economy really grows. There is no fixed ceiling: trees keep growing, more slowly above 150 m. If real GDP is missing, GDP at current PPP or in current USD is used and marked.

Crown

Width: diversity of the economy — export mix (1 − concentration of fuel, food, ores and manufactures), manufacturing and services shares, and low dependence on natural resource rents. Density and colour: the quality-of-life pillar. A rich country relying on one industry has a green but narrow crown.

Roots

Six roots, each a percentile score: education (lower-secondary attainment, secondary and tertiary enrolment), health care (physicians, DPT immunization, child mortality), clean water, electricity, internet and institutions (government effectiveness). Depth, thickness, branching and root hairs grow with the score; roots below 30 show dead sections.

Problems and military

Dry branches, brown leaves and falling leaves grow non-linearly as the problems pillar falls. The steel-blue branch shows military strength: the percentile average of military expenditure (USD), armed forces personnel and arms exports (SIPRI TIV). It can be hidden.

Estimated age of the nation

NationsTree measures nations, not today’s borders. The age is counted from the oldest scientifically confirmed statehood of the nation (for example Poland 966, the Baptism of Poland under Mieszko I; China about 1600 BC, the Shang dynasty; Japan about AD 250, the Yamato polity). Traditional or legendary dates (Japan 660 BC, China’s Xia dynasty) are shown next to it for context but do not count. Each date has a source. Where no earlier statehood is documented, the founding date of the present state from Wikidata (P571) is used. The full list is on the nation age ranking.

4. Limitations

  • Statistics differ in coverage and timeliness; small territories and countries in conflict often have gaps.
  • Percentiles describe relative position, not absolute quality. Changes in the set of reporting countries can move percentiles slightly.
  • The index is a summary for orientation; for decisions use the underlying indicators, which are all shown with sources.

Questions or corrections: every page links to its sources. Methodology changes are versioned; the version is printed on every page and export.

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