Looking for a good book to read? If you want one that won't bore you halfway through, mathematics professor Jordan Ellenberg has an interesting tip: look at the Kindle highlights.
His theory: if the most popular highlights occur in the first half of the book, it might mean that people aren't reading it all the way through:
How can we find today's greatest non-reads? Amazon's "Popular Highlights" feature provides one quick and dirty measure. Every book's Kindle page lists the five passages most highlighted by readers. If every reader is getting to the end, those highlights could be scattered throughout the length of the book. If nobody has made it past the introduction, the popular highlights will be clustered at the beginning.
Thus, the Hawking Index (HI): Take the page numbers of a book's five top highlights, average them, and divide by the number of pages in the whole book. The higher the number, the more of the book we're guessing most people are likely to have read. (Disclaimer: This is not remotely scientific and is for entertainment purposes only!)
Of course, this has a few downsides. Not only is it not "remotely scientific", but it only works with books you actually have — it doesn't work with samples (annoyingly). However, if you like to grab books from the free Kindle Lending Library (or you use the new Kindle Unlimited), you could check a book's highlights before you start reading.
It's not a perfect trick, but it's a clever one that's worth keeping in your back pocket if reader reviews don't leave you feeling confident.