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. 2018 Jan;7(1):89–96.

Table 2.

Tests for readability analysis

Test Score Type Qualities Assessed Formula
Flesch-Kincaid Reading Ease Index score range (0-100, where 100=easiest) Word complexity, sentence length 206.835 – (1.015 x ASL) – (84.6 x ASW)
Flesch-Kincaid Grade Level Word complexity, sentence length (0.39 x ASL) + (11.8 x ASW) - 15.59
Gunning Fog Score Grade Level Word complexity, sentence length 0.4 (ASL + PHW)
Coleman Liau Index Grade Level Word complexity, sentence length 0.0588L – 0.296S – 15.8
SMOG Index Grade Level Word complexity, sentence length 3 + Square Root of Polysyllable Count
Automated Readability Index Grade Level Word complexity, sentence length 4.71 (characters/words) + 0.5 (words/sentences) – 21.43

ASL: Average sentence length (i.e., the number of words divided by the number of sentences); ASW: Average number of syllables per word (i.e., the number of syllables divided by the number of words); PHW: Percentage of hard words; L: The average number of letters per 100 words; S: The average number of sentences per 100 words