My new publishing series continues today with a post from April Hamilton called “How Meaningful A Metric Is Your Book’s Amazon Sales Rank?”, which is, obviously, all about the sales rank on Amazon. It makes for some pretty interesting reading. Check the links is April’s bio at the end, as there’s some good stuff in there. All yours, April:

How Meaningful A Metric Is Your Book’s Amazon Sales Rank?

Ah yes, the Amazon Sales Rank: that addictive bit of eye candy that can lift an author’s spirits into the stratosphere one day and hurl him down onto the rocks the next. In all likelihood neither reaction is truly justified, because a book’s Amazon Sales Rank is a temporary, relative thing, and does not mean what many authors think it does. If you want to get to the bottom of what your book’s ASR means, you might start by thinking about what the ASR does not mean.

First, it does not reflect a cumulative sales count. Let’s say Amazon has 1 million titles listed for sale on its site—it actually lists many more than that, but let’s keep the math simple. Let’s further say that Amazon opened its virtual doors exactly one year ago today, and your book is currently ranked #500,000. It would seem logical to assume the book that has sold the fewest copies over the past year would be ranked #1,000,000, the one that has sold the most copies would be ranked #1, and yours, ranked at #500,000, has sold exactly 499,000 fewer copies than #1 and 499,000 copies more than #1,000,000. But this is not true at all. Your book’s ASR is based on a much more complex algorithm that’s considered a trade secret by Amazon.

Second, your book’s ASR is not a dynamic line such as one might see on a sales chart, moving reliably upward each time a copy sells, and just as reliably downward when others’ books are selling and yours is not. ASR is recalculated hourly, and only includes titles that actually had sales activity during the hour in question, or were ranked within the top 100 in any category during that hour. This is how it’s possible for your book’s ASR to sometimes be higher than that of multi-million-selling books by authors along the lines of JK Rowling and Stephen King; if neither of them sold any copies in a given hour when you sold 2 copies of your book, your book’s rank will be higher than theirs’ for that hour. Your book is only being ranked relative to the performance of a small subset of all the books being offered for sale by

Regarding that term, “sales activity,” shopping cart returns and other unusual circumstances are included under this umbrella. For example, if many copies of another book are sold and then returned in the same hour, that other book will take a Rank hit and every other book that shares a category with that book may get a Rank bump. Amazon will not reveal the specifics of precisely how it calculates rank, but I have observed this phenomenon with my own books—though not consistently.

Reconsider the above statement: Amazon will not reveal the specifics of precisely how it calculates sales rank. The formula is just as hotly debated, and about as arcane, as the answer to the question of how Google calculates its Page Ranks. However, in its Help pages Amazon openly states it does not share actual sales numbers for any product listed on its sites for “competitive reasons”. So the answer to the question, “What does my book’s Amazon Sales Rank mean?” is, strictly speaking, “No one really knows, except the keepers of Amazon’s ranking algorithm.” That doesn’t mean your book’s ASR is totally meaningless, though.

As your book’s ASR goes up, so does its visibility on the Amazon site, especially if you can crack the top 100 in any popular category. This is because Amazon provides hyperlinked top 100 lists in every major category right on its site. Your book is more likely to be noticed by folks browsing the site by category if it’s on one or more of those lists, and this tends to be come a self-feeding loop. More people see your book, which leads to more sales, which drives your ASR up, which leads to more people seeing your book, et cetera, et cetera. Also, the higher your book’s sales rank, the more likely it is to be recommended as a ‘buy this book and that book together’ candidate on other popular books’ product pages. This is the thinking behind the “Amazon Rush” book marketing tactic, in which you try to get as many people as possible to buy your book on the same day. If your rush is successful, your book gets that self-feeding ASR – visibility – sales cycle going.

Finally, note your book won’t have an ASR at all until at least one copy sells. From then on, it should continue to be ranked until it’s removed from sale by you or Amazon.

Apart from the context of a first sale, an Amazon Rush, or the top 100 best seller list in any category, you can’t really extrapolate all that much of value from your book’s Amazon Sales Rank. Feel free to go back to obsessing about your follower count on Twitter, instead. 

April L. Hamilton is an author, author services provider, and the founder and Editor in Chief of Publetariat. Her most recent book is The Indie Author Guide: Self-Publishing Strategies Anyone Can Use.