All readability formulas are based on the average number of syllables per word and words per sentence. They are most easily and accurately applied using computer software. Three formulas useful in rating health education materials are the Fog index used mainly in education, the Flesch formula used in the insurance industry to check the readability of policies, and the Flesch-Kincaid formula used to check manuals produced for the US armed services. Checklist Reading level tests lower than the ability of most readers. Reading level is consistent throughout the material.
Language is simple, conversational.
Words, Sentences and paragraphs are short.