Readability Formulas

The breakthrough of readability formulas was the publication of The Teacher's Word Book by Edward Thorndike in 1921. In his book, Thorndike tabulated the frequency of difficult words used in general literature. For the first time, a notable scholar suggested a means to measure difficult words through mathematical formulas.

Early researchers tabulated surface characteristics of written texts to determine the extent readers could comprehend texts. Then they compared the data with certain predetermined standards; one such standard was tabulating the average grade level of students who could correctly answer a certain percentage of questions from the text. The characteristics with the most accurate standards were judged as indices of readability. These characteristics were worked upon and developed into readability formulas.

Read more: The History and Development of Readability Formulas

Despite their much-criticized shortcomings, many organizations consider readability formulas an important tool to evaluate the readability of text. Here are reasons why you should use readability formulas in your organization:

1. Most Americans have limited reading ability, which means their reading grade-level balances between average and poor. It makes sense to prepare text in plain English if your readers have limited reading capabilities. How do you determine if your text is readable from your readers' point of view? Simple. Use readability formulas.

2. If the text is not readable, the purpose of writing it in the first place gets defeated. For instance, let's assume you've written an instruction manual for your employees. If your employees cannot read this manual, they will never understand the true meaning of its contents; this will adversely impact their productivity. Using readability formulas can prevent such a scenario and tell you beforehand if your text is of any value to your employees.

Read more: Why Use Readability Formulas?

Presently, there are more than 200 readability formulas developed by various scholars since the 1940s. Only a handful of these formulas are reliable to determine the reading-level of a sample text. This article will help you to decide which readability formula or formulas to use on your documents. Identify your industry, then select the appropriate formula.

EDUCATION

The primary role of the education sector is to distill good education to students at different grade levels. Written text in the form of textbooks, journals, literature and so on, forms the backbone of a good education system. Here are different readability formulas to use on your documents according to the grade level:

1. Dale-Chall: Dale-Chall Readability formula is a general formula suitable for all kind of texts.

2. Spache: Spache Readability Formula is ideal for the texts aimed at up to 3rd grade level students.

3. Powers-Sumner-Kearl: The Powers-Sumner-Kearl Readability Formula is ideal for text geared towards primary age children (age 7-10).

4. SMOG: McLaughlin's SMOG Readability Formula is appropriate for the text aimed at secondary age (4th grade to college level) readers.

5. Flesch Reading Ease: The Flesch Reading Ease Readability Formula is a general formula suitable for all kind of texts.

6. Gunning Fog: The Gunning Fog Index Readability Formula is ideal for education material aimed at business houses, like business magazines and journals.

7. Fry Graph: The Fry Graph Readability Formula is a general formula suitable for all kind of texts.

8. Coleman-Liau: The Coleman-Liau Readability Formula is ideal for the text aimed at 4th grade to college level readers.

9. McAlpine EFLAW: The McAlpine EFLAW Readability Formula is ideal in determining the ease of reading English text for ESL/EFL (English as a Second/Foreign Language) readers.

Read more: How Do I Decide Which Readability Formula To Use On My Document?

Your writing skills may be superb, but what if your readers can't understand your text? Technically, your readers may have problems with your document's "readability," but what truly counts is the document's "understandability." Most average literate Americans can read a well-crafted document; the question is will readers understand the text in the same manner you want them to? This is where determining the "understandability" of your documents makes more sense. A scholarly piece of text is of no value to a sixth grade readability level reader. Similarly, a disoriented piece of writing makes no sense to a reader with a twelfth-grade readability level. It's always advised to determine the reading level of the text for the targeted readership before publishing it.

A handful of popular readability formulas are available to address this issue. These formulas apply a mathematical application to a text to determine its readability grade level.

Read more: Can Readers Understand What I Write?