The Harry Potter Effect

When a new Harry Potter book comes out, you can feel it in the winds. Everyone—from publishers to booksellers to readers—can't help but get caught up in the industry-wide updraft. And while it's no surprise that a new Harry Potter book (especially one that's officially part of the now eight-part series) will sell well, it's interesting to note how a new release affects the sales of other books in the Potterverse. With this summer's release of Harry Potter and the Cursed Child, are people buying more Harry Potter colouring books? Are they rushing out to buy editions of the first, second, or third books in the series? And if so, have those sales dropped off or gone up in the week after the release?

Because you know we can't pass up an opportunity to combine our love of both charts and Harry Potter, we took to SalesData to investigate.

We looked at the sales trends for all ISBNs with "Harry Potter" in the title, series name, or subtitle, focusing on the last 13 weeks ending Aug. 7, 2016. The below chart shows sales trends for the 10 ISBNs with the most units sold in that period (minus Cursed Child, of course, which would've been literally off the charts).

As you can see, sales for the other titles in the Harry Potter series climbed steadily in the weeks leading up to the release of Cursed Child, in some cases jumping significantly the week leading up to and following July 31, 2016. It's interesting to note that the book with the biggest sales jump is Fantastic Beasts and Where to Find Them, which is very likely influenced by the upcoming release of the film adaptation and, relatedly, increased stock levels and marketing. In the second and third spots are the first two books in the series: Philosopher's Stone and Chamber of Secrets, perhaps purchased for a new generation of readers or people who have finally succumbed to Pottermania and decided to hop aboard the Hogwarts Express. While all the books in this chart saw increased sales in this 13-week period, it's only with the two colouring books on the list that you see a slight decline or plateauing after the release of Cursed Child, showing a preference among book buyers for the novels during this particular week.

If you look back at the release of the seventh book in the series, Harry Potter and the Deathly Hallows, on July 21, 2007, you can see a similar effect on other books in the series. We looked at the same 13-week period for this release, highlighting the sales trends for the top 10 ISBNs with "Harry Potter" in the title, series name, or subtitle at the time:

Almost across the board, you can see two ISBNs for each title, which generally account for the hardcover and paperback editions, topped by the hardcover edition of Chamber of Secrets and the paperback edition of Half-Blood Prince. The most notable change in this case is a sudden drop in sales for the Half-Blood Prince trade paperback after July 21 (although it still outsold the other eight ISBNs on this list), possibly owing to a marketing push for the sixth book that ended when the seventh came out.

Also of note when we compare the graphs from 2007 and 2016: the noticeable lack of colouring books and spin-off books (we're looking at you, Fantastic Beasts) back in 2007, perhaps deserving of a nostalgic nod to simpler times.

Of course, the Harry Potter Effect isn't just limited to a 13-week period; it's a year-long phenomenon. So let's look at the sales of all those books with "Harry Potter" in the title, series name, or subtitle for the last 52 weeks ending Aug. 7, 2016. Over the last year, these were the top-selling Harry Potter books in volume sold:

  1. Harry Potter and the Cursed Child (Scholastic Inc. 9781338099133 HT $39.99 July 31, 2016 JUVENILE FICTION)
  2. Harry Potter: The Coloring Book (Scholastic Inc. 9781338029994 TP $21.99 Nov. 10, 2015 JUVENILE NON-FICTION)
  3. Harry Potter and the Philosopher's Stone (Bloomsbury 9781408855652 TP $12.10 Sept. 30, 2014 FICTION)
  4. Harry Potter and the Philosopher's Stone: Illustrated Edition (Bloomsbury 9781408845646 HT $49.99 Oct. 6, 2015 JUVENILE FICTION)
  5. Harry Potter: Magical Creatures Coloring Book (Scholastic 9781338030006 TP $21.99 Jan. 26, 2016 JUVENILE NON-FICTION)
  6. Fantastic Beasts and Where to Find Them (Bloomsbury 9781408803011 TP $9.99 Aug. 25, 2009 FICTION)
  7. Harry Potter and the Chamber of Secrets (Bloomsbury 9781408855669 TP $12.50 Sept. 30, 2014 FICTION)
  8. Harry Potter and the Prisoner of Azkaban (Bloomsbury 9781408855676 TP $12.50 Sept. 30, 2014 FICTION)
  9. Harry Potter: Magical Places and Characters Coloring Book (Scholastic 9781338030013 TP $21.99 March 29, 2016 JUVENILE NON-FICTION)
  10. Harry Potter and the Goblet of Fire (Bloomsbury 9781408855683 TP $16.00 Sept. 30, 2014 FICTION)

The list shows an interesting mix of novels, colouring books, and the illustrated edition of Philosopher's Stone, though it didn't outsell the paperback edition from 2014. In fact, all the paperback editions released in 2014 continue to be big sellers. There are, of course, a few frontlist titles here, too, demonstrating a continued demand for new Harry Potter books in the market.

But while Cursed Child and the above colouring books are the biggest new Harry Potter titles in the market, there are actually a total of 23 ISBNs with "Harry Potter" in the title, series name, or subtitle published in 2016 that saw at least one unit sold in the last 52 weeks. These range from a guide to Harry Potter-themed crafts to a new boxed set for spin-off books Quidditch Through the Ages and The Tales of Beedle the Bard. In fact, over the last year, there were 281 "Harry Potter" ISBNs in a wide range of subject categories that saw at least one unit sold, including books categorized under Literary Criticism, Music, Philosophy, Political Science, and surprisingly (or, perhaps, unsurprisingly) Games / Magic.

In short, we can't seem to quench our thirst for books set in or discussing the Potterverse. Keep 'em coming!