Table I.

Description of readability tools and their corresponding formulas.

Readability tool	Formula
Flesch-Kincaid Reading Ease Score	Readability Ease = 206.835−(1.015 × Average Sentence Length)−(84.6 × Average Number of Syllables per Word)
Gunning Fog	Grade Level = 0.4 × (Average Sentence Length/Percentage of Hard Words)
Flesch-Kincaid Grade Level	Grade Level = (0.39 × Average Sentence Length) + (11.8 × Average # Syllable per Word)−15.59
The Coleman-Liau Index	Grade Level = 0.0855 × (Average # of letters per 100 words)−0.296 × (Average # of sentences per 100 words)−15.8
SMOG Index	Grade Level = 3 × Square Root of Polysyllable Count
Automated Readability Index	Grade Level = 4.71 × (characters/words) + 0.5 × (words/sentences)−21.43
Linsear Write Formula	n = [(2 Syllables words ∗ 1) + (3 or more syllable words ∗ 3)]/Number of Sentences
	If n < 20, Grade Level = n/20
	If n > 20, Grade Level = n−2/20

SMOG, Simple Measure of Gobbledygook.