We can dissect the term “readability” into “read” + “ability,” which translates into the ability to read. Readability has nothing to do with either legibility or literacy. In fact, readability is more of a judgmental exercise for the targeted audience. George Klare (1963) defines readability as “the ease of understanding or comprehension due to the style of writing.” We can consider readability as a measure of the accessibility of a text or the associated page layout, indicating how effectively it will reach the target audience.

We can assess readability through readability tests by applying readability formulas. Readability formulas are mathematical in nature; its primary aim is to measure the grade level a person must have to read and comprehend a text. Writers consider readability formulas as simple ways to judge read-ability, i.e., the level of difficulty of a text.

Readability formulas work by measuring certain features of a text based on mathematical calculations. We base these readability measures on a handful of factors, like the number of words in a sentence, as well as the number of letters or syllables per word. Most readability formulas are based on one semantic factor, i.e., the difficulty of words, and one syntactic factor, i.e., the difficulty of sentences. We don’t need to calculate other factors, as they tend to make the formulas more complex and achieve little in return.

Another startling fact about these formulas is that you don’t need readers to read out (or try to read out) the text. However, readability formulas don’t always work with 100% accuracy.

Importance of Readability Formulas

It requires a great deal of effort to come up with some kind of text. This text may be unique in its contents, yet it fails to serve its purpose of making the reader understand and use it. The problem many writers face is how to assess the ‘readability’ of their text. Readability formulas offer the solution. By applying these scientific and mathematical principles, the readability formulas aim to present an objective analysis about the readability of a particular text.

Commonly used Readability Formulas

Researchers and writers have been using readability formulas since 1920 and, over the years, they have spent a lot of time devising the most accurate and scientific formulas to assess readability. Some of the popular and commonly used formulas include:

1. Rudolph Flesch’s Reading Ease Formula;
2. Flesch’s Grade Level;
3. J. Peter Kinkaid’s Flesch-Kinkaid Index;
4. Robert Gunning’s Fog Index;
5. The SMOG Readability Formula;
6. Fry’s Readability Graph;
7. New Dale-Chall formula;
8. Powers-Sumner-Kear Readability Formula;
9. FORCAST readability formula; and
10. Spache readability formula.

The underlying message of each formula is the same: if you use shorter, average sentence lengths and fewer big-lettered words, you can reduce the reading level and increase the speed and ease of reading.

ABOUT THE AUTHOR
Brian Scott is a contributing writer for Lousy Writer where he helps writers and non-writers how to write better.