Ever since my start in writing, I’ve thought
Rudolph Flesh devised the Fog Index. I even vaguely remember someone assigning another “G” and calling it the
Recently I learned that Robert Gunning was the author
of the Fog Index and Rudolph Flesch devised the Readability Formula. Both teach writers to write more plainly and therefore
make their articles more interesting to the average reader.
I found an article by Tom Davey of Canada,
who has written four books and therefore has had occasion to put his theories into practice. He said Gunning’s Fog Index
is probably the most used, as it results in how much education is required for comprehension. Low scores are desirable, scores
above 20 are regarded as incomprehensible. Fog indices are on many computer programs, he says.
Here’s the way it works:
a medium-length paragraph, about 120 words.
the number of words in the sample.
the number of sentences.
the words by the sentences to get an average of words per sentence.
each word of three or more syllables, excluding short words made longer by adding another short word (butterfly, for instance)
or verbs that gained their extra syllables by adding ed or es; or words that begin with a capital letter or that are the first
word in any sentence.
Once you have the polysyllable count, add that number
to the word average.
Multiply by .4; that's point-4, or four-tenths.
The result is your Fogg Index number. The higher the
number, the more difficult the reading. A score of 17 means only a graduate student could understand
your copy; a nine means a ninth grader could understand. Business Week averages a 10, the Gettysburg Address gets 10 and Time
and Newsweek work out to about 11.
The best way to improve your readability scores is
to make “The Elements of Style,” a small but packed-with-good-rules book, one of your major resources in learning
good writing. Early copies had only 75 or so pages but subsequent editions tip the scales over 80 pages. If you’re serious
about writing, be sure to get a copy for your reference shelf.
(NCWritertoo is a retired journalist
who worked as a writer for over 25 years. Email her at firstname.lastname@example.org)