Books

# The Hawking Index Is a Mathematical Measure of When People Give Up on Books

How many times can one person start to read "Moby Dick" and stop halfway through? Or "Infinite Jest," for that matter? And what about Stephen Hawking's "A Brief History of Time," widely called "the most unread book of all time?"

A mathematician has an answer, as they so often do. To find out whether you're likely to give up on a book, look no further than the "Hawking Index," a fun, if imprecise, mathematical measure of how far, on average, people get into a given book. It was invented by mathematician Jordan Ellenberg in a blog for the Wall Street Journal.

Before we get into how you can calculate the Hawking Index for a book you're reading, one caveat: When Ellenberg first proposed the Hawking Index in 2014, this process was free. At the time, everyone could view the five most-highlighted passages on any book's Kindle page. That's not true anymore: To view popular highlights on a Kindle these days, it has to be a book you've bought. If you'd rather not, never fear: You can still see the Hawking Index of many popular books later on in this article.

What Ellenberg hypothesized while building his index was this: If people read all the way to the end of a book, the highlights will be scattered evenly throughout. If everyone stops right after reading the introduction or first chapter, the highlights will stop there too.

To find out what a book's Hawking Index is, first turn to Amazon's "Popular Highlights" feature on your Kindle. Then, average the page numbers of the book's top five highlights and divide that average by the number of pages in the book. That'll give you a percentage. The higher the percentage, the more likely it is that people read all the way to the end. The lower the percentage, the less likely it is that anyone got past the first half.

Imagine a 100-page book. If all five top highlights appear on page 100, the Hawking Index will be 100 percent. That means that most people, according to Ellenberg, will probably read all the way to the end. But if the average top highlight appears on page 2? That's not a good sign.

## Disclaimer: This Is Not Remotely Scientific

By this point, you might be starting to think that the Hawking Index sounds fun, but also pretty flawed. Isn't there a better way to figure out how often people finish books? What about people who don't highlight while they read? What if people just highlight when they start reading and then stop as they keep going? What about people who don't even use Kindles to read?

Yep, the Hawking Index is imperfect. And Ellenberg himself agrees. In his original blog post, he included a disclaimer before announcing the most- and least-read books of the summer: "This is not remotely scientific and is for entertainment purposes only!"

And the entertainment is great. The Index's namesake, "A Brief History of Time" by Stephen Hawking, scores 6.6 percent on the Index, while David Foster Wallace's "Infinite Jest" scores 6.4 percent. Each of those, however, is better read than Thomas Picketty's "Capital," which lands at only 2.4 percent. But Donna Tartt's "The Goldfinch," which was just made into a movie, scores a whopping 98.5 percent, which means all of the top highlights land at the end of the book.

If all this talk makes you feel sad for neglected books, bought only to languish on a shelf or a Kindle library, you can take action to rescue books from oblivion. Brad Bigelow's Neglected Books Page collects and reviews the forgotten books of the past and attempts to resurrect them. Some books are just born in the wrong time, chosen and discarded, and then picked up again later. And some books remain unread forever.