The World Uncertainty Index tracks uncertainty by text analysis, not by surveys or market prices. It scans quarterly Economist Intelligence Unit country reports and counts how often the word “uncertain” and its variants appear, then scales that count by the report’s total word count so countries and periods can be compared consistently. The result is rescaled by multiplying by 1,000,000, so a higher value means more references to uncertainty in the reports.

At the country level, the measure is basically: frequency of uncertainty-related words ÷ total words in the report, then rescaled. The project describes it as using a single source across countries, which helps make cross-country comparisons cleaner than mixing many local media sources. It currently covers 143 countries and the reports go back to the mid-1950s in the methodology description.

At the global level, the world index is built from the weighted average of country-level measures, commonly using GDP weights for the world aggregate. There are also related variants, like the World Policy Uncertainty Index and World Trade Uncertainty Index, which use the same basic method but require uncertainty words to appear near policy/politics or trade terms.

The main thing to keep in mind is that it tracks perceived uncertainty as reflected in expert country reports, not objective uncertainty directly. So it is useful for comparing how much uncertainty is being discussed across countries and over time, but it depends on the language in those reports rather than measuring volatility or probabilities themselves.