JK Rowling, The Cuckoo's Calling, and Regression to the Mean

You've probably heard by now that JK Rowling published a crime novel in April 2013 under the secret pen name Robert Galbraith. There's been a huge amount of buzz about the novel, titled The Cuckoo’s Calling, since the news was broken. The press has focused mainly on two details. First, the novel came out to a very good critical reception, including a starred review from Publisher's Weekly. And second, the book sold quite poorly in its first three months -- 1500 copies in Britain. (Since Galbraith’s real identity was revealed, of course, the book has rocketed up the bestseller charts.)  (Edit:  Shad has pointed out a source saying that the book sold  comparably to similar debuts, and sales numbers were actually similar to Harry Potter in its first few months.  So "poorly" might be too strong of a word.)

I was really excited to hear the news. I loved the Harry Potter series. Though I didn't read The Casual Vacancy since it seemed too literary for my tastes, The Cuckoo’s Calling is definitely something I'll be adding to my to-read list.

I've also enjoyed reading online reactions as the news broke. In some ways, they’ve been a litmus test of peoples’ underlying views on the publishing industry. Some people, like author Nathan Bransford, have written about how the book's poor sales illustrate the fleeting nature of publishing success. Others commentators took this as more evidence that publishers no longer have anything to offer writers.

And what’s my reaction to the Rowling story? It’s to recall a statistical principle known as regression to the mean.



Regression to the mean roughly says that any instance of superlative performance will likely be followed by a mediocre performance. For example, a student pilot who lands a plane exceptionally well is likely to make a mistake the next time around. An athlete who wins an Athlete of the Year award will have a surprisingly ho-hum record the following year. And the top performing branch of a chain restaurant is likely to show less growth than its peers the next year. So on, and so forth…

What causes this? When asked to explain this phenomenon, people come up with myriad reasons. Perhaps the pressure of doing so well the first time made the student pilot choke on the second landing. Maybe the Athlete of the Year got too confident and partied too much, which hurt her future performance. Maybe the restaurant branch got lazy and stop recruiting customers after their good year.

All us could possibly be true, but there is another, simpler explanation.

Think about it this way. In order to be exceptional in any field, what has to happen? Well, you'll likely have to be good at what you do. That's a given. But skill is not enough. To be an extreme success, all the stars have to align in your favor. The weather has to be perfect for your landing. You have to hit the winning shot in that crucial game. You have to have some unexpected influxes of restaurant customers. In other words, you have to be very, very lucky.

So what happens the next year? Well, your skill remains high. But what are the chances of everything going in your favor again? Your luck will most likely be average the second time around, and you overall performance will drop accordingly.

So you can see where this is going. Both Harry Potter and The Cuckoo’s Calling were well-written books. One was a commercial slamdunk that made Rowling the world's first billionaire author. The other didn't do as well, at least not within its first three months. Why is this? Did the book have a less commercial premise?  Was three months too slow to find an audience? Did the publisher screw up? Was there a secret alien conspiracy? We'll probably never know all the details. But before jumping to conclusions, make sure to take into account that humble principle known as regression to the mean.

Readers, what's your reaction to The Cuckoo's Calling?  Will you read it?


(BTW, If you’re interested in reading more about this and other types of statistical reasoning, check out Thinking Fast and Slow, by Daniel Kahneman.)


Hope you enjoyed this post! To get regular updates from this blog, use the subscription options on the sidebar.  By the way, friend of the blog Kristen Kittscher recently released her debut MG mystery The Wig in the Window.  Here's the blurb. 

 Best friends and seventh graders Sophie Young and Grace Yang have made a game out of spying on their neighbors. On one of their midnight stakeouts, they witness a terrifying, bloody scene at the home of their bizarre middle-school counselor Dr. Charlotte Agford (also known as Dr. Awkward).

At least, they think they do. The truth is that Dr. Agford was only making her famous pickled beets. But when Dr. Agford begins acting even weirder than usual, Sophie and Grace become convinced that she’s hiding something—and they’re determined to find out what it is.

Soon the girls are breaking secret codes, being followed by a strange blue car, and tailing strangers with unibrows and Texas accents. But as their investigation heats up, Sophie and Grace start to crack under the pressure. Will solving the case destroy their friendship?


Check it out!