World Uncertainty Index (WUI) was constructed for an unbalanced panel of 143 individual countries on a quarterly basis from 1952. This is the first attempt to construct a panel uncertainty index for a large set of developed and developing countries. The index reflects the frequencies of the word “uncertainty” (and its variants) in the Economist Intelligence Unit (EIU) country reports. To make the WUI comparable across countries, authors scale the raw counts by the total number of words in each report — the number of “uncertainty” words per thousand words.