About Readability

Readability refers to certain qualities of written text, with respect to being legible/decipherable and/or easy/enjoyable to read. A comprehensive definition of readability, although referring to printed materials it is still applicable to text in any format, has been given by Edgar Dale and Jeanne Chall (1949):

“The sum total (including all the interactions) of all those elements within a given piece of printed material that affect the success a group of readers have with it. The success is the extent to which they understand it, read it at an optimal speed, and find it interesting.”

When designing a website or trying to share/convey information in written format, it is important to make sure that the presentation style (e.g. length of sentences, grammar, difficulty of words) is not a barrier. On the other side, texts that are too easy to read may fail to engage the reader because they are boring.

Selected Readability References

  1. The Principles of Readability. Impact Information.
  2. Writing for Every Reader.
  3. Readable: What is Readability?
  4. Ultimate guide to blog readability.
  5. Design guidelines for web readability. Proceedings of the 2017 Conference on Designing Interactive Systems,
  6. Can readability formulas be used to successfully gauge difficulty of reading materials?
    • Begeny, J.C., Greene, D.J. (2013). Psychology in the Schools, Wiley Periodicals. Doi: 10.1002/pits.21740.
  7. A comparison of features for automatic readability assessment.
    • Feng, L., Jansche, M., Huenerfauth, M., Elhadad, N. (2010). Proceedings of the 23rd International Conference on Computational Linguistics, pp. 276-281.

Video explanation of readability:

Readability Score Tools

A readability score is a computer-calculated index indicating the level of education a reader should have in order to understand the written text being assessed. Readability scores, in addition to pointing out problems, are also providing tools to solve readability issues. A number of formulas are used to measure readability, some of them providing the output in the form of a score (e.g. Flesch-Kincaid Reading Ease, Spache Score, New Dale-Chall Score) which needs to be interpreted, while some other provide directly the readability grade levels (e.g. Flesch-Kincaid Grade Level, Gunning-Fog Score, Coleman-Liau Index, SMOG Index, Automated Readability Index). Various free online tools have been implemented to automatically calculate readability and to analyze text clarity and content: