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Note: Slate initially posted a version of this column before it was finished being edited. A correction at the end of the article details errors that appeared in the original.
Walk into a bookstore, and it can seem as though every book is billed as a "national best seller." It's not hard to explain why: There are numerous best-seller lists on which to base the claim, and the lists don't always anoint the same books. On Thursday, for example, six of the most prominent top-10 fiction lists included 22 different titles. How do these best-seller lists work? And why don't they all list the same books?
There hasn't always been such an abundance of lists. According to Michael Korda's Making the List, the first best-seller list in America began in 1895 as a monthly column in a now defunct literary magazine called The Bookman. The oldest continuously published list was introduced in 1912 by Publishers Weekly, and the New York Times Book Review began publishing its list as a regular weekly feature in 1942. Now there are more than 40 best-seller lists that report how well books are doing either nationally or in various segments of the market—in particular regions, at certain chain stores, at independent bookstores nationwide. However, no list-maker tracks every book sold in the country; even the national lists draw on a sample of actual sales data from booksellers and use it to extrapolate total national sales.
The industry bellwether is the New YorkTimes list, due to the prominence of the newspaper and the scope of its sales survey. Each week, the Times receives sales reports from almost 4,000 bookstores, along with reports from wholesalers that sell to 50,000 other retailers, including gift shops, department stores, newsstands, and supermarkets. John Wright, the assistant to the best-sellers editor at the Times, said the paper does not reveal the precise methodology by which its list is compiled. But we do know that the rankings are based on unit, not dollar, figures and account for sales during a Sunday to Saturday week.
To report sales to the Times, booksellers use a form provided by Times editors. The form lists titles the editors think are likely to sell well. Although there is space below for writing in additional titles, this practice has been controversial. Some critics (particularly independent-bookstore owners and small publishers) believe the Times form makes it more difficult for quiet, word-of-mouth hits to make the Times list. Whatever the cause, the Times list certainly makes "mistakes": A recent study of best sellers by Alan Sorensen, an assistant professor at the Stanford Graduate School of Business, found 109 hardcover fiction books that did not make the Times list in 2001 and 2002 but sold better than some that did.
Other best-seller lists draw on smaller survey samples. The San Francisco Chronicle and Los Angeles Times (among other newspapers) publish lists that rank sales in their regions. Barnes & Noble and Amazon calculate best-seller lists based exclusively on their own sales—the Barnes & Noble list includes transactions both on the company's Web site and at its more than 870 stores. The American Booksellers Association's "Book Sense" list surveys only independent bookstores, compiling data from about 460 of the estimated 2,000 independent bookstores in the United States. (And Library Journal,a trade magazine, even launched a list recently that is not based on sales at all; instead, it ranks the books "most borrowed" from libraries.) Best-seller lists generally separate hardcover and paperback books and also parse by category: fiction, nonfiction, advice, children's, etc. There are exceptions: Barnes & Noble, for example, lumps together hardcover and paperback sales while retaining the distinction between fiction and nonfiction, and USA Today runs a single, unified list of the top 150.
Since the many lists represent different pieces of the total book-sales pie—and even those representing the same slice use different samples—there can be some startling divergences among the rankings. (Some lists are also faster than others to record sales, which can exaggerate these differences.) For example, on Wednesday, Skinny Dip by Carl Hiassen ranked No. 10 among the ABA's independents but only came in at No. 121 on USA Today's list. The No. 7 book on Amazon, War Trash by Ha Jin, was not in Barnes & Noble's top 25 while the No. 3 book on Barnes & Noble, Anita Shreve's Light on Snow, was only No. 22 on Amazon—and neither book had yet made it onto the Times or Publishers Weekly lists.
Best-seller lists indicate how a book is selling relative to other books in a given geographical area or niche of the market, but they don't reveal how many copies a book has sold or how much money consumers have spent on a given title. Movie buffs can log onto the Internet Movie Database and find out how much money a film took in at the box office the week before. But readers who love The Da Vinci Code by Dan Brown, which just had a long run at No. 1 on almost every fiction best-seller list, have no way to tell from the rankings whether it is selling 1,000 copies a week or 1 million, or how much money it has made.
In part, definitive figures on book sales don't appear in best-seller lists because timely, authoritative data can be hard to come by, even for publishers. The larger companies, such as Holtzbrinck (FSG, Holt, Picador, St. Martin's) or Bertelsmann (Random House, Knopf, Doubleday) have increasingly sophisticated in-house systems that update sales data for their own titles on a weekly or daily basis, based on figures that sales reps get from book retailers across the country. These systems have blind spots, however: Airports and supermarkets, for example, are slower to report point-of-sale data, so it can sometimes take two to three months for publishers to obtain sales numbers from these venues. And publishing house bean-counters must also contend with the book world's peculiar return policy, which allows retailers to send any books they cannot sell back to the publisher—for a full refund. Only when a book is bought and retained by the customer does it count as a sale for the publisher. As a result, for the publisher, sales figures are always provisional pending a costly adjustment for returns—and returns can be huge, sometimes amounting to between 40 percent and 50 percent of books shipped.
So how many books do you actually need to sell to make it onto, say, the Times list? There is no defined threshold, but according to the Stanford study, one book made the hardcover fiction list selling only 2,108 copies a week; more typically, the median weekly sales figure in the study was 18,717. And most books can't keep even these modest sale rates up for long: Sales generally peak during a book's second week on the list and then steadily decline. Over a period of six months, the median best seller in the Stanford study averaged weekly sales of just over 3,600 copies.