The Automated Readability Index (ARI) is a readability test designed to gauge the understandability of a text. Like the Flesch-Kincaid Grade Level, Gunning-Fog Index, SMOG Index, and Coleman-Liau Index, its output is an approximate representation of the U.S. grade level needed to comprehend the text.
Unlike the other indices, the ARI, along with the Coleman-Liau, relies on a factor of characters per word, instead of the usual syllables per word. Although opinion varies on its accuracy as compared to the syllables/word and complex words indices, characters/word is often easier to calculate, as the number of characters is more readily and accurately counted by computer programs than syllables.
Formula
To calculate the Automated Readability Index:
- Divide the number of characters by the number of words, and multiply by 4.71. This is #1.
- Divide the number of words by the number of sentences, and multiply by 0.5. This is #2.
- Add #1 and #2 together, and subtract 21.43.
Flying over the oak tree, the farmer saw the flock of birds that had damaged his crops.
Ironing out all wrinkles, the pants looked much more presentable
External links
- Online readability tests - finds ARI and other indices, suggestions how to improve readability