Math is tricky

Some more unreliable numbers have come out about e-books, and Dean Wesley Smith continues to insist that e-book sales are flatlining. He makes a fairly common error when he tries to evaluate the significance of the "fact" that e-book sales were 17% of the market in 2011 and 23% of the market in 2012:

Yup, that’s 23%. A 6% difference over a full year.

Hello, that's also a 35% growth rate. What will the book market look like if this growth continues? Like this, only faster.

David Gaughran takes a shot at reading the tea leaves as well, and I think he does a better job (in no small part because he is willing to acknowledge that we don't actually know much). I agree with him that it's impressive that 25% of books sold on Barnes & Noble are self-published, despite the fact that B&N does a notoriously craptacular job selling both e-books and self-published books.

Just to give you an idea of how quickly a troubled industry can implode, here's a chart on Passive Voice about ad revenues (i.e. the major source of revenues) for newspapers. Note how until about four years ago, it would have been fairly easy for wishful thinkers to trick themselves into believing that the industry was going to survive the Internet.