Runaway Plain-Language Blockbuster

Dan Brown's Secret Weapon

OF the millions of words written about Dan Brown's The Da Vinci Code, few have mentioned the effect of its 7th-grade level of readability on its success. A few critics actually condemned its ease-of-reading as a liability rather than the key to its massive audience.

Anyone not aware of The Da Vinci Code has been living under a rock for the last three years. Since the publication of the novel in 2003, the literary world has talked of nothing else. While it started life as just another mystery novel, the book soon moved into history as one of the most successful books of all time and sending Dan Brown into literary superstardom.

Whatever you think about the book, it is hard to escape these measures of success:

Language to Shout About

For publishers and writers, it is no secret that simple language is a key ingredient of success. As we pointed out in our May 2005 Newsletter, what writers have in common like Steven King, Tom Clancy, John Grisham, Clive Cussler, and Michael Crichton is that they all write at the 7th-grade level.

Although many ingredients go into a blockbuster such as this, we cannot ignore the snappy prose that carries the reader briskly from one short chapter to the next. If there is a lesson here, it is that plain language is the key to a brilliant writing career.

The Simple Measure of Gobbledygook (SMOG)

McLaughlin: still searching for a better formula.

Harry McLaughlin's Easy Formula

THE SMOG readability formula has long been one of the most popular formulas, mainly because of its reliability and ease-of-use. A Google search for "SMOG formula" will bring up 554,000 hits.

The formula is the creation of G. Harry McLaughlin, who has spent much of his life in applied psychology.

Harry started his career as a sub-editor of the Mirror newspaper in London, one of the largest and most readable newspapers in the world.

He left the newspaper to pursue a doctorate in psycholinguistics at the University of London. His thesis, "What Makes Prose Understandable," showed why the readability formulas work: the lengths of words and sentences are good predictors of textual difficulty.

After teaching human communications at City University of London, he moved to Toronto, where he taught briefly at York University and then to the University of Syracuse, where he published his SMOG formula in 1969.

Harry worked two years with NASA, helping them develop procedures for staffing Mission Control in Houston. Then he taught at the Ontario Institute for Studies in Education.

The Quest for a Better Formula

What had originally inspired Harry was the desire to improve on the available formulas. Believing that the vocabulary and sentence features of a text interact with one another, his formula multiplied them instead of adding them as other formulas did.

The SMOG formula requires counting the number of words with more than two syllables in 30 sentences (the polysyllable count) and then applying this simple formula:

SMOG grade = 3 + square root of polysyllable count.

Harry validated his formula against the McCall-Crabbs reading tests, using a 100% correct-answer criterion. As a result, his formula generally predicts scores higher than other formulas.

Fortunately for us, Harry's interests have again returned to finding a better formula. While working on that, he has put his current formula on his Web page, where you can paste and test your documents:


The page also features three of Harry's original articles on readability.

Download It Now—Free!
The Principles of Readability
By William H. DuBay

A brief introduction to the research on the readability formulas.
70 pages, bibliography

"Thanks for the report on readability. It is really a very impressive work. You have pulled together a lot of information that ranges over a long period of time. A genuine work of classic scholarship—of which there is way too little that comes my way."
—Thomas Sticht, Ph.D., International Consultant on Adult Literacy

"I finally got around to reading your article. It is very good, scholarly, and complete. Even though readability formulas have been around for years, I think that the biggest current problem is that they are not widely used. Much education of writers, editors, and general population is needed."
—Edward Fry, Ph.D. Reading Consultant.

"I just wanted to tell you how much I appreciated the level of scholarship in your amazing work, The Principles of Readability.
—Eldon McMurray, Ph.D. Candidate, Utah Valley State College.

Plain Language in the News

Plain-language labels required for allergens:

Don Watson profile:

Fed still not speaking plain English:

Push for plain English in Queensland schools:

Confusion in park-strip planning:

Sick of English: http://blogg.aftonbladet.se/1366/perma/11097/

Straight talk on financial literacy:

The law in plain English:

Why official English must be forever plain:

Drug ads for cancer patients difficult to read:

Unparliamentary language: