Which readability index is characterized by counting the average number of syllables per sentence?

The Gunning FOG Index is designed to assess the readability of English texts by calculating the average number of words per sentence and the percentage of complex words—those with three or more syllables. A key aspect of this index is its emphasis on the intricacy of words, which indirectly relates to counting syllables, as complex words typically contain more syllables. This makes the Gunning FOG Index particularly useful for determining how easily a reader can understand a text, especially in educational contexts or professional writing.

By focusing on the average sentence length and the use of complex words, the Gunning FOG Index provides valuable insight into the complexity of written material, which is vital for tailoring communication to a specific audience. The other indices mentioned may have their own methodologies and criteria for assessing readability, but they do not specifically center around the average number of syllables per sentence as the Gunning FOG Index does. This is what distinguishes it in terms of measuring readability based on syllable counts and associated complexities.