In a recent post by Seth Godin he discussed the correlation between selling and reading in the pre- and post-internet eras. He concluded with a footnote worthy of further discussion:

An example of this is the publishers and authors that oppose libraries and the lending of ebooks. In these cases, even though money was paid, they’re apparently against being read–even though there’s zero evidence that library reading hurts book sales.

Prima facie there's plenty of evidence that library lending hurts book sales; once a book is read its value has been extracted and there is a disincentive to then purchase the book. A quick check around the Red Hill Publishing office suggests that very few books borrowed are then purchased (to the point of statistical insignificance).

However—and it’s a big however— I expect that those who choose to source reading material from their library rather than a book store are not even in the market to buy the book. Libraries and book stores are economic substitutes.

Interestingly we hear complaints from the content industries, particularly the record industry, that online piracy hurts (record) sales. To my mind there's no doubt that's true. Yet an "illegal" download doesn't always equal a lost sale if the downloader was never going to buy the record. That's where the statistic analysis needs to take place and that's where it's absent.

Hit me up on Twitter if you'd like to discuss this, or just shoot the breeze: @robertcollings.