Test | Formula |
---|---|
Flesch Reading | FRE = 206.835 − (1.015 × average sentence length*) |
Ease* | − (84.6 × average number of syllables per word) |
Flesch-Kincaid** | FK = (0.39 × average sentence length+) + (11.8 × average number of syllables per word) − 15.59 |
SMOG# | SMOG = 3 + √(polysyllable count)† |
↵* FRE scores range from 0–100, with 0 representing “practically unreadable” text and 100 representing text that is “easy for any literate person.”
↵** FK readability test is intended to indicate the US grade level, or number of years of education needed to comprehend the written text30.
↵+ Average sentence length: average number of words per sentence.
↵# Information should be written at a grade 6 SMOG level to ensure that material is understandable for patients with low literacy23. Higher scores correlate with higher US grade levels.
↵† To calculate the polysyllable count: count every word with > 3 syllables in each group of 10 sentences (1 group from the beginning, from the middle, and the end of the text, respectively)18. SMOG: Simple Measure of Gobbledygook.