What are Readability Metrics?


When analyzing content using Scribe in Content Manager, one metric displayed at the top of the page are your content's Readability Metrics. This is a collection of metrics which have been analyzed using several different systems for rating your content's easiness to read, complexity and more.

The following indexes, tests and metrics are used in making this determination:

  • Flesch-Kindcaid Reading Ease: The Reading Ease score is the oldest readability score, commonly used in academics and government and incorporated into most word processing software. The Flesch-Kincaid Reading Ease score is the result of a mathematical formula that incorporated the average number of syllables per word and the average number of words per sentence for the 100-word block of text. Results are measured on a scale from 1 to 100, with 1 being very complicated to read and 100 being very easy to read. Most readability resources recommend writing for the 60 to 70 range.
  • Flesch-Kincaid Grade Level: Like the Flesch-Kincaid Reading Ease score, this is a mathematical formula that measures syllables and sentences length. However, the results are given as an academic grade level, from 0 to 12. Negative results are rated at 0 and any grade level over 12 is listed as 12. The Flesch-Kincaid Grade Level score was developed after the Reading Ease score to make it easier for parents, librarians and others to make decisions about reading content for children. The recommending writing level here depends on your audience, but 7th to 8th grade is a good standard — that captures more than 80% of the U.S. adults.
  • Gunning-Fog Score: The Gunning Fog index takes into account "complex" words, those with three or more syllables, as part of its mathematical formula for readability. It also omits proper nouns, jargon and compound words. The result is a grade-level score beginning at 1 with no upper bound. According to UsingEnglish.com "the New York Times has an average Fog index of 11-12, Time magazine about 11. Typically, technical documentation has a Fog Index between 10 and 15, and professional prose almost never exceeds 18." The ideal score is between 7 and 8, depending on your audience.
  • Coleman-Liau Index: Unlike most other readability tests, the Coleman Liau Index relies on the number of characters instead of syllables per words for its calculation. It returns a U.S. grade-level score from 1-12. The recommended writing level for this score is 7 to 8, depending on your audience.
  • SMOG Index: It's debatable whether SMOG is short for "Simple Measure of Gobbledygook," but this index developed in 1969 is still a common measure of readability. Take 30 sentences (10 from the beginning, middle and end of your text), then count every word with three or more syllables in each group of sentences, then calculate the square root of that number and round it to the nearest 10, then add 3 to that number. You have the U.S. grade level that should be able to read that text. The recommended grade level for this score is 7 to 8, depending on your audience.
  • Automated Readability Index: The Automated Readability Index (ARI) mathematical formula has two variables: characters per word (instead of syllables, similar to the Coleman Liau Index) and words per sentence. It has been around since 1967. Its scores correspond to U.S. grade level. If you get a score with a decimal, round up to the next whole number. Again, the recommended reading level is 7 to 8, depending on your audience.
  • Word Count: Determines the total number of words included in the content.
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