From graphic author Colleen Doran:
Today, authors and publishers increasingly rely on services like Bookscan to track their sales, to commodify popularity into a contract for the next gig. If a publisher thinks you have “millions of fans,” naturally a publisher will want to sign up your new novel.
. . . .
I track my own sales as listed by Amazon Author Central (which gets its data from Bookscan) against my actual sales as listed on my royalty statements, and I find Bookscan is so far off as to be completely useless. I’ll show you what I mean with examples below. These Bookscan numbers can have a serious effect on an author’s ability to sell a project, and if they are as wrong as I know they can be, this muddle can cripple a career.
. . . .
OK, so let’s have a look at one of my books published after Amazon linked to Bookscan. I am not going to tell you what this book was, just that it is a book from a major publisher.
According to Bookscan, it has sold 542 copies in hardcover. Ouch. What a bummer! This is accurate as of yesterday.
Except I got a royalty statement on this thing. And according to my royalty statement, this book sold 7181 copies by end of the accounting period, which was last summer. As of now, it has sold over 10,000 copies in hardcover. Respectable numbers. Not tearing up the charts, but enough to issue a new edition.
So, the accumulated Bookscan numbers are a good 93% off my actual reported sales from my publisher, as of my last royalty period.
. . . .
I’ve been told many times, and have often repeated here, that Bookscan numbers are half to one quarter of what your actual numbers are. But in my experience, it is 90% or more off on every single one of my books. No exceptions. (EDIT: I checked one other book after writing this, and it fared a bit better: about 80% off.) The numbers are so far off, at first I assumed that these Bookscan numbers were just showing me books sold on Amazon. But not according to Author Central
Link to the rest at A Distant Soil and thanks to Anthea for the tip.
UPDATE: Sorry for the bad image file insertions. They should be fixed now.