Bestseller Math Archive pick
November 12, 2001
Nationwide bestseller! Number two with a bullet! Box-office smash! Popularity and the economics of profit go hand-in-hand. Bestseller lists in the world of books, top 40 charts for music, weekly ratings of television shows, and Hollywood reports on movie box-office receipts not only provide us with a barometer on our popular culture, but also serve an important marketing purpose.

Take book bestseller lists as an example. A book that makes it to the top of the New York Times bestseller list can proudly display "#1 New York Times Bestseller" on its book jacket. The publishers hope that you will be in a bookstore, see the book, and think, "If everyone else is reading it and buying it, then why aren't I?"

There are many book bestseller lists, but the most widely discussed and quoted lists appear in the weekly New York Times Book Review. When those lists change, it's news. In late July of 2000, the New York Times restructured its bestseller lists for the first time in 16 years. Among the changes was the addition of children's book lists. And the reason for the changes was... Harry Potter.

Up until the change in the New York Times bestseller lists, its main bestseller list for fiction had been dominated by the books in the Harry Potter series by J. K. Rowling. Not coincidentally, the New York Times made the change just as the fourth book in the series was being released. Creating the children's bestseller lists meant that the New York Times could move the Harry Potter books off the "main" hardcover fiction list and onto the new children's list.

In an interview with the Boston Globe, New York Times Book Review editor Charles McGrath gave this reason for the changes, "The sales and popularity of children's books can rival and, in the case of the Harry Potter books, even exceed those of adult books. With a separate children's list, we can more fully represent what people are reading, and we can clear more room on the adult list for adult books." Supporters of the move — particularly publishers other than Harry Potter publisher, Scholastic Press — were happy to see the hardcover fiction list opened up for different books (i.e. their books).

Not everyone was convinced. Critics claimed that the New York Times was out of touch with the public, that a large percentage of the series' readers were adults, and that any books that sold as well as the Harry Potter books deserved to be on the main bestseller list. But the list changes remained and, rather than Harry Potter appearing in four of the top ten spots in the main hardcover fiction list, Harry Potter "disappeared" onto the children's lists.

Teaching the Problem
Some book bestseller lists, such as the one published in USA Today, represent the raw data of actual book sales. But raw numerical data isn't the only way to represent something's popularity. The New York Times "weights" its list, so that the numbers are an interpretation of the raw data. The Nielsen ratings tell how many people viewed a particular television show as a percentage of all possible viewers watching television at that hour and on that day. And we hear about how successful or popular movies are when the movie industry tells us how much money the movie "raked in" at the box office. In non-Hollywood terms, the "gross" represents how many people bought tickets to see that movie, expressed as the total amount of money those people spent for those tickets.

Students can learn about collecting and representing data in the following Destination Math activities from the MSC V module, Fundamental Statistics:

  • Exploring Bar Graphs: Students compare sales data for a single product from five different cities and display the data on a bar graph. Ask students how they would translate the bar graph to a list. The session's workout questions deal with number of households watching the top four news programs. Ask the students to make a TV rating list based on the data given in the workout.

Destination Math

Analyzing the Problem

  1. Have students read the article, "Why 'Harry Potter' did a Harry Houdini" and compare the data source of the New York Times bestseller list with that of's "Hot 100" list. Here are questions they may want to consider:

    • Are these two bestseller lists drawing on similar samples? How are the samples similar? How are they different?
    • How might the differences in the sample sets affect the raw data?
  2. Have students look at the Publishers Weekly article, "Bestsellers of 1999—Hardcover: So Far, Little Has Changed." At the bottom of the article, they will find a fiction and a nonfiction list of the top 15 hardcover sellers in 1999. Draw a bar chart for each of the lists.

  3. Have students examine this week's USA Today's Top 150 best-selling books list and answer these questions:

    • Can you draw a bar chart representing the top 10 sellers? Why or why not?
    • If the #1 book has been on the list for 2 weeks, and the #2 book has been on the list for 4 weeks, can you determine which book has sold more copies? Why or why not?
    • Does the number of book sales correspond to numbers of readers? Why not? (Hint: Do you buy every book you read?)

Casting a Sales Spell
When the latest Harry Potter volume, Harry Potter and the Goblet of Fire, was released in July 2000, it had the largest first printing in publishing history — 3.8 million copies. Even that incredible number wasn't enough and the supply quickly sold out. Rowling's US publisher, Scholastic Books, had to quickly print an additional 3 million copies.

Fun in Misfortune
Harry Potter isn't the only must-read for students these days. While all four Harry Potter books are in the New York Times top ten children's chapter books list, another four of the top ten books are from the Series of Unfortunate Events series by Lemony Snicket. Dark and smartly funny, these books chronicle the unlucky lives of the three Baudelaire children, orphaned from the opening pages of The Bad Beginning, the first book in the series. There's danger and gloom on every page of these mock Gothics. But it's hard not to recommend books with face-snapping crabs and names like Carmelita Spats and the Prufrock Preperatory School.

More Links
Students who enjoy the Harry Potter series can find related information, games, and goodies at Scholastic's Harry Potter site, at Bloomsbury's Welcome to Harry Potter Books, and at other sites listed at The Top Ten Harry Potter Sites.

Fans of the Series of Unfortunate Events books can find even more woe and misfortune at or check out an interview with the elusive author.

Extending the Problem
  1. Temple University professor of mathematics John Allen Paulos writes a monthly column, "Who's Counting?" for He addressed the issue of top 10 lists in the article, "The Rankings Game: Mirror, Mirror, Who's the Most Beautiful of All?"

  2. Students can look at current lists and ratings, and learn more about how ratings are created, at the following sites:


Related Activities
Must-see TV
This Riverdeep Current story examines the Nielsen ratings and why companies care so much about what you watch.