STC India Blog

The Art and Science of Readability

A crucial role of every writer and editor is to ensure readability of a document, amongst other factors such as accessibility, legibility, and usability. Readability is a measurable concept and many tests are available to calculate readability score. This post talks about the Flesch-Kincaid readability test that is inbuilt in the MS Word and MS Outlook applications.

Definition: Simply defined, readability is the level of ease or difficulty in reading and understanding a piece of text. Flesch-Kincaid readability test calculates a readability score based on the following inputs:

  • Semantic that is related to vocabulary and checks for words in a sentence that is not available on a plain language word list.
  • Syntactic that defines sentence complexity based on the sentence length and the average number of words per sentence.

Scores Quick Reference: The Flesch-Kincaid Grade Level Readability score is a number ranging from 0 –100. A higher score indicates a text that is easy to read. Use this quick reference to decide how readable your document is in the content of your target audience.

  • 0–100.0 = Easily understandable by an average 5th grader.
  • 0–70.0 = Easily understood by 8th and 9th graders. This score is recommended for most standard documents.
  • 0–30 = Easily understood by college graduates.

Other Readability Tests: You can read about other readability test indices, such as Coleman Liau index, Automated Readability Index and SMOG on Wikipedia.  To start with run a readability test using this online utility that calculates scores based on a combination of readability tests. Whatever be the formula you choose to calculate readability, the point that is driven home is that short, simple sentences with words in plain language make a text easy to read and understand.

Example: See how the number and complexity of words affect the readability score in the following sentences:

Sentence Flesch Reading Score Flesch-Kincaid Grade Level
The cat is on the mat. 100.00 0
The cat lay on an ornate carpet. 90.9 2.3
The feline lay supine on a lavish carpet with exaggerated tassels. 41.8 10

If you are experimenting with writing styles or practicing plain and simple writing then use the readability score as a measurement tool to assist in decision-making and further editing.

Try It: Turn on the auto-feature in MS Word or MS-Outlook to calculate the Flesch Reading Score and Flesch-Kincaid Grade Level of an existing piece of writing and then edit the same content as follows:

  1. Reduce the number of words in a sentence keeping the word count between 20-24 words per sentence.
  2. Use short words with as few as 5 characters per word.
  3. Divide you text into paragraphs (as many as possible) with not more than two or three sentences in a paragraph.
  4. Convert passive sentences to active.

Caution: Readability formulas do not have 100% accuracy because they discount the presence of the human factor. For example, a reader with prior knowledge of a subject may be able to understand a more complex piece of writing on the subject. George Klare, who significantly contributed to the field of readability warned, “Do not rely on formulas alone in selecting materials; seek the opinion of experts or get reliable consensus opinions to examine characteristics that formulas cannot predict . . . .”

Your technical editor can provide you with expert judgment and content organization expertise. Always get your documents reviewed and edited, irrespective of what the automated readability scores predict. Remember, good writing is an art, a creative endeavor, complemented by rules and metrics.

About the Author
Aneesha Myles Shewani is a technical editor, working primarily on application user manuals and end-user training material. She is currently employed with Fiserv and has expertise in establishing style guides and editorial standards for print, online and mobile media. She spends her leisure time in reading and writing about a variety of topics, ranging from history to science fiction. Aneesha also writes fiction and some of her work can be read on her blog: