SMOG

A readability formula developed by G. Harry McLaughlin in 1969 that estimates the years of education needed to understand a text, based on the number of polysyllabic words (three or more syllables) in a fixed sample of sentences. SMOG is widely used in healthcare communication and plain-language work because it correlates reasonably well with comprehension at higher grade levels and is easy to compute by hand. Like other shallow readability formulas, SMOG ignores sentence structure, vocabulary familiarity, and discourse coherence, so it should be treated as a rough indicator rather than a reliable measure of accessibility.