The One Way Bestsellers Have Changed That You Probably Haven’t Noticed

Jamie Chung for reader’s Digest (photograph) and Joel Holland for reader’s digest (hand lettering)If you’ve ever read a Dr. Seuss book, you may be familiar with words such as Fizza-ma-Wizza-ma-Dill, Fiffer-feffer-feff, and Truffula. You may also be familiar with these words: a, will, the.

Besides made-up words and rhymes, Dr. Seuss’s biggest trademark is simple writing. We can partly thank William Spaulding, his Houghton Mifflin editor and the director of its educational division at the time, who wanted Seuss to go after an even younger audience than he had reached with his first books, Horton Hears a Who!, And to Think That I Saw It on Mulberry Street, and If I Ran the Zoo. Spaulding’s challenge: “Write me a story that first graders can’t put down!”

Spaulding sent along a list of about 350 words with the instructions to make a book out of them. The result, The Cat in the Hat, clocks in at 236 words and ranks as the second-­highest-selling book of Seuss’s career. The book ahead of it? Green Eggs and Ham, which uses just 50 words­—all but one of them one syllable. (The long one: anywhere.)

Seuss’s word selection came from lists created by readability experts such as Rudolf Flesch, who argued in his seminal 1955 book Why Johnny Can’t Read that literacy education in America needed reform. It was Flesch who introduced the nation to phonics, which enabled students to sound out words rather than having to memorize them. He also helped to create a mathematical formula, the Flesch-Kincaid Grade Level test, to measure the complexity of military training manuals. It and another similar test are now commonly applied to insurance policies and other official documents, but it makes for a handy literacy scale as well.

The formula itself is fairly simple: .39 (total words/total sentences) + 11.8 (total syllables/total words) – 15.59

The resulting score is the grade level required to understand the text. If a book gets a 3, that means you’d need at least a third-grade education to under­stand it.

For instance, Green Eggs and Ham actually yields a score of −1.1. On the other end of the spectrum: Absalom, Absalom! Because William Faulkner frequently disregards punctuation, it contains one “sentence” composed of 1,288 words, earning that passage a grade-level score of 503.

As part of my research, I collected every digitized number one New York Times bestseller from 1960 to 2014 and ran the Flesch-Kincaid test on all 563 of them. Most books meant for a general audience will fall within the fourth- to eleventh-grade range, as did all of these bestsellers. If you look at the scores over the decades (see chart below), an unmistakable trend becomes clear: The bestseller list is full of much simpler fiction today than it was 40 or 50 years ago. In the 1960s, the median book had a grade level of 8. Today the median grade level is 6.

On the upper end, James ­Michener’s 1988 novel Alaska had a grade-level score of 11.1. Of the books I analyzed, 25 had a grade level of 9 or higher. But just two of these were written after 2000.

On the low end, eight books tied for the lowest score of 4.4. All were written after 2000 by one of three high-volume writers: James Patterson, Janet Evano­vich, and Nora Roberts.

There’s no way around it: While prizewinning literary novels such as Jonathan Franzen’s The Corrections make the number one spot on occasion, overall, the books we’re reading have become simpler. They aren’t the only example of words that seem less wise today. For instance, presidential State of the Union addresses have gone from a 17th-grade level pre-1900 to a 12th-grade level in the 1900s to below a 10th-grade level in the 2000s, prompting a Guardian headline to declare, “The state of our union is … dumber.” Does that mean that books—and therefore their ­readers—are getting “dumber” too?

It is true that today’s bestsellers have much shorter sentences than the bestsellers of the past, a drop from a median of 17 words per sentence in the 1960s to 12 in the 2000s. Also, today’s list is much more often topped by commercial novels than in the past.

This supports my “guilty pleasures” theory. Of course, there have always been “guilty pleasure” books on the list. In the 1960s, it was Valley of the Dolls; in the 1970s, The Exorcist; in the 1980s, the Bourne books; and in the 1990s, the Jurassic Park sequel, The Lost World.

But if we break down bestsellers by genre, we find that there has been a long-term shift within these guilty pleasures. Thrillers have become “dumber.” Romance novels have become “dumber.” There has been an across-the-board “dumbification” of popular fiction. Among current authors who have written at least five number one bestsellers, most, including Stephen King, Danielle Steel, and Harlan Coben, rank at or below the sixth-grade level.

It would be easy to lump in the New York Times list’s reading-level decline with the rise of knee-jerk argu­ments that the country’s intellect is at an all-time low, but I don’t think this is fair.

Writing doesn’t need to be complicated to be considered powerful or literary. The winner of the 2014 ­Pulitzer Prize for fiction, The Goldfinch, was also a bestseller and has a reading level of 7.2. While many classics have high scores (The Age of Innocence at 10.4, Oliver Twist at 10.1, The ­Satanic Verses at 10.1), just as many have surprisingly low scores: To Kill a Mocking­bird at 5.9, The Sun Also Rises at 4.2, and The Grapes of Wrath at 4.1. These books are revered, but they are also accessible enough to be taught in middle and high school.

It’s logical that our bestselling books are not complex—by definition, popular means they appeal to the masses. For what it’s worth, plenty of successful “literary” writers have embraced the beauty of “easy” writing.

As one bestselling writer put it, “One day I will find the right words, and they will be simple.” His name: Jack Kerouac. By the way, Kerouac’s most popular book, On the Road, scores a reading level of 6.6.