Gunning fog index

Introduced by Gunning in 1952, the Gunning Fog Index (GFI) is a measurement (or at least estimate) of the “formal education a person needs to understand the text on the first reading”. (@martinc2019, 143)

$GFI=0.4(\frac{totalWords}{totalSentences}+100\frac{longWords}{totalSentences})$ where longWords > 7 characters

• Keywords: readability
• Source: @martinc2019
• Related: flesch-kincaid-readability-tests