Here’s How to Put the the Flesch in and Take the Fog Out of Your Writing

November 18, 2008 by Michael Alexander · Leave a Comment

You’ve just completed a bit of writing for your Web site or blog and you’re happy with the results. Well, what about your readers? Do you think you’ve written at a level that’s appropriate for their education and ability to make sense of what you’ve written?

How to determine readability of one’s writing has been a topic of discussion among scholars for close to 100 years and in that time they’ve developed a variety of formulas that aim to get at the heart of the question.

Two of the best known readability formulas are the Flesch-Kincaid and the Gunning Fog Index. Both are similar in that they look at the number of syllables per word and number of words per sentences and calculate the grade level required to understand the text.

I wouldn’t rely exclusively on readability formulas because the level of literacy today is lower than in previous generations but either can be helpful in reminding you to write succinctly and with clarity.

U.S. government agencies use the Flesch Reading Ease Readability Formula as their standard readability formula. It’s so popular that Microsoft Word, Google Docs and other writing apps can calculate readability based on the Flesch formula for you.

The Flesch Reading Ease Readability Formula

ASL = Average Sentence Length (the number of words divided by the number of sentences)
ASW = Average number of syllables per word (the number of syllables divided by the number of words)
RE = Readability Ease
RE = 206.835 – (1.015 x ASL) – (84.6 x ASW)

The result is a number between 0 to 100. The higher the number, the easier the text is to read.

90-100 : Very Easy
80-89 : Easy
70-79 : Fairly Easy
60-69 : Standard
50-59 : Fairly Difficult
30-49 : Difficult
0-29 : Very Confusing

To put that into perspective, Reader’s Digest has a readability index of about 65, Timescores about 52, and the Harvard Law Review scores in the low 30s.

Microsoft Word will calculate the Flesch Reading Ease Index for you. On the Tools menu, click Options, and then click the Spelling & Grammar tab. Select the Check grammar with spelling check box. Select the Show readability statistics box, and then click OK. On the Standard toolbar, click Spelling and Grammar or hit F7. When Word finishes checking spelling and grammar, it displays information about the reading level of the document.

Gunning Fog Readability Index

Back when I was in grad school, chiseling my term papers on stone tablets, I had a writing prof who hammered into my loopy little head how to write lean and athletic prose. One of his bibles was The Technique of Clear Writing, by Robert Gunning. Gunning also devised a method of measuring the readability of text called the Gunning Fog Index.

Gunning died decades ago and his book is out of print, although you can still find used copies online and at your local library. I got to thinking about Gunning’s principles and wondered if they would still hold up today, especially for Web writing.

You know what? For the most part, they still do (you probably saw that coming). So, in an abbreviated form, here are Gunning’s “10 Principles of Clear Statement” (Adapted from “The Technique of Clear Writing,” rev. ed. New York: McGraw-Hill Book Company, 1973):

Keep sentences short. Fifteen to twenty words per sentence is a good average.
Prefer the simple to the complex. Writing shorter sentences usually means you use shorter words. Instead of “utilize” write “use,” and instead of “modification” write “change.”
Use the familiar word. Intelligent people use their large vocabularies only to impart clear, exact meaning—not to show off. Big minds use little words; little minds use big words.
Avoid unnecessary words. You can often cut your writing in half and still say the same thing. Use “to” instead of “in order to,” for example.
Put action in your verbs. “The fullback hits the line.” That’s writing with an active verb. “The line is hit by the fullback.” That’s writing with a passive verb. The snap of action is gone.
Write like you talk. “Write like you talk” is poor grammar, but Gunning’s point is that you should adopt a natural, conversational writing style.
Use terms your reader can picture. Avoid fuzzy words like “conditions,” “situations,” “facilities,” “inadequacies.”
Tie in with your reader’s experience. To get your words read, understood and accepted, you must have a clear understanding of your own purposes and those of your readers.
Use variety. Good writers work within a strict discipline of simplicity. However, they vary sentence length, structure, and vocabulary so their writing does not seem choppy or childish.
Write to express, not impress. No writing is easy. However, we make it more difficult by using long, unfamiliar words, and in writing long, meandering sentences.