Gunning's FOG index is calculated from:
This is one of the indexes which concentrates on long words. Another is the SMOG index. In Readability,
a long word is defined as one of 3 or more syllables. Of course, words
such as "altogether" are long words by this definition (it has 4
syllables) but it is a familiar word. It seems that words with many
syllables do make writing harder to read, even though they are familiar
words.
