WHIPPING up good data journalism can involve painful research and number-crunching. The hacks at Delayed Gratification, a quarterly magazine that produces a slower, more reflective type of journalism, have achieved this with striking results. They combed through E.L James’s "Fifty Shades of Grey" trilogy, a best-selling series of safe-for-suburbia kinky novels, to identify, categorise and quantify the salacious bits. The result is a seductive infographic that shows when and where the naughty parts crop up, and how elaborate it is. The data reveal some interesting trends.

In the later books readers need only read the first 40 pages before the friskiness begins, whereas in the first novel they had to wade through twice that. And each successive tome contains less sex than the last, as an absolute number and as a proportion, giving you much less bang for your book. Yet later titles score higher on the ‘kinkiness index’, which tracks the use of apparatus, originality of venues and level of rough romance. We've republished the chart below, and we asked Rob Orchard, the editor of Delayed Gratification, to tell us the story behind it. (The original chart is online here.)

Q&A with Rob Orchard, editor of Delayed Gratification magazine:

What gave you the idea to create a data-visualisation of the book? Were you adapting a technique that you had seen before?

The idea to pull together the data came from that old story about copies of "Lady Chatterley's Lover" falling open on the "interesting" bits, which made us think we should provide a user's guide to the "Fifty Shades" books. We were spurred on by the secret code we kept hearing between people reading the books on the train–"Have you reached page 348 yet?” As for the design, we’d not seen anything similar before: we wanted to present the data in a clean, almost clinical way.

How did you determine the two lower bar charts ("kinkiness" and "agglomerated") and the scale; that is, what "data" do they represent? Or is it, shall we say, a "subjective quantification"?

An infographic like this is always going to have a slightly subjective and impressionistic element to it—what one person thinks of as the height of sauciness, another will see as unexceptional—but we tried to make it as scientific as possible. We mapped out the sexual acts, locations and paraphernalia for the books, then rated them against scales we had created, running from 1 (Vanilla) to 5 (Kinky). So the sex acts scale ran from foreplay to flogging, sex locations ran from “in the imagination” to the infamous Red Room of Pain, and sex paraphernalia ran from Ben and Jerry’s ice cream to leather shackles and vibrating wands. The Agglomerated Kinkiness Index just pulls together all three ratings to provide an overall kink reading. What are the one or two revelations that the charts uncovered that you hadn't known, or like best? It’s interesting that the sex levels tail off in the third book ("Fifty Shades Freed") after Steele and Grey are married. However, they do have some of their kinkiest sex in this novel: it contains one of only two sessions rated at 15/15 on the Agglomerated Kinkiness Index in the entire trilogy. Explain Delayed Gratification: when were you established, by whom and why?