Editing Flesch–Kincaid readability tests (section)

==Flesch–Kincaid grade level== <!-- Redirect to section from [[Flesch–Kincaid Grade Level]] -->
These readability tests are used extensively in the field of education. The "Flesch–Kincaid Grade Level Formula" presents a score as a [[Education in the United States#School grades|U.S. grade level]], making it easier for teachers, parents, librarians, and others to judge the readability level of various books and texts. It can also mean the number of years of education generally required to understand this text, relevant when the formula results in a number greater than 10. The grade level is calculated with the following formula:<ref name="Kincaid1975">{{cite journal |vauthors=Kincaid JP, Fishburne RP Jr, Rogers RL, Chissom BS |author-link=J. Peter Kincaid |date=February 1975 |title=Derivation of new readability formulas (Automated Readability Index, Fog Count and Flesch Reading Ease Formula) for Navy enlisted personnel|url=https://apps.dtic.mil/sti/pdfs/ADA006655.pdf |archive-url=https://web.archive.org/web/20201210212716/https://apps.dtic.mil/sti/pdfs/ADA006655.pdf |url-status=live |archive-date=December 10, 2020 |journal=Research Branch Report 8-75, Millington, TN: Naval Technical Training, U. S. Naval Air Station, Memphis, TN.}}</ref>

<math display="block">
0.39 \left ( \frac{\mbox{total words}}{\mbox{total sentences}} \right ) + 11.8 \left ( \frac{\mbox{total syllables}}{\mbox{total words}} \right ) - 15.59
</math>

The result is a number that corresponds with a U.S. grade level. The sentence, "The Australian platypus is seemingly a hybrid of a mammal and reptilian creature" is an 11.3 as it has 24 syllables and 13 words. The different weighting factors for words per sentence and syllables per word in each scoring system mean that the two schemes are not directly comparable and cannot be converted. The grade level formula emphasizes sentence length over word length. By creating one-word strings with hundreds of random characters, grade levels may be attained that are hundreds of times larger than [[high school]] completion in the United States. Due to the formula's construction, the score does not have an upper bound.

The lowest grade level score in theory is −3.40 (belonging to the passage "Go. See. Stop. Rest." for example), but there are few real passages in which every sentence consists of a single one-syllable word. ''[[Green Eggs and Ham]]'' by [[Dr. Seuss]] comes close, averaging 5.7 words per sentence and 1.02 syllables per word, with a grade level of −1.3. (Most of the 50 used words are [[Syllable|monosyllabic]]; "anywhere", which occurs eight times, is the only exception.)