How fast does Amazon Sales Rank drop? Two case studies

I track the Amazon Sales Rank of two books after a single sale, and am floored by the results

Question: How fast does Amazon sales rank plummet after one sale?

I set out to answer the question: How fast does a book hit a 5 million Amazon sales rank after it sells? Or 10 million? I decided there were a couple ways to answer this.

One was to pick a random book from me inventory, and when it sells, track its sales rank each day (until it sells again). The problem with this approach is that most of the books in my inventory are going to sell before they hit 5 or 10 million sales rank.

I had another idea…

How a failed book project taught me a lesson on Amazon Sales Rank

One of my side businesses is publishing. I have about 10 titles in print, on subjects unrelated to selling on Amazon. Most of my titles are very “long tail” books that sell steadily but infrequently. Most sales come through Amazon. Cumulatively, they bring me in a small amount of supplemental revenue every month.

I have a couple of titles in print, however, that almost never sell. I decided I could track one of these “rarely selling” books, next time one sells. It would be a simple way to track how quickly Amazon Sales Rank plummets for a very poorly selling title.

Three months I published a book that I thought would sell well. We’ll just say it was targeted to the “computer hacker” niche. I couldn’t have been more wrong about this one. The book sold  a single copy the day after going live on Amazon – and never sold another copy to this day.

But it did provide the perfect case study for tracking a poorly-selling title on Amazon. Specifically, how quickly the Sales Rank of a book can plummet.

Here’s what I saw when a low-demand book sold a single copy

It was published on November 15th, and sold a single copy the next day, bringing its rank to approximately 150,000. Then (as I said), it never sold another copy.

Here’s what I found: Today, just over 3 months later, the book is ranked 6.5 million. It went from 150,000 to 6.5 million in three months.

Keep in mind an Amazon Sales Rank of 6 million is considered toxic by nearly every Amazon seller. I.e. most booksellers would never touch a book ranked 6 million. But 3 months isn’t that long ago.

When I noticed this book’s sales rank the other day, I was totally floored that a book could go from a sale to 6 million in only 3 months.

A second example, with a different lesson

In mid-August (6 months ago), I purchased a book with an Amazon Sales Rank of 400,000. It had just sold a copy at $200 (according to CamelCamelCamel.com). I had the only copy for sale on Amazon (and still do), so I priced the book at $499.95. The book hasn’t sold in those 6 months.

So what happened to the sales rank a 400k-ranked book in 6 months? If the last example went from 150k to 6.5 million in 3 months, certainly this title would be ranked 12 million? Or 10 million? Or some higher number?

No. The book currently has an Amazon Sales Rank of 3.5 million.

How could a book that sold 6 months ago have a sales rank of 3.5 million, yet a book that sold 3 months ago have a sales rank of 6.5 million? The answer is pretty simple: Amazon’s algorithm factors past sales history into the sales rank of an item.

After a single sale, the Amazon sales rank for some items rise upwards more slowly than others. The book that has sold one copy in its history will drift upwards much more quickly than a book that has sold two copies a year for 10 years.

We now know Amazon takes into account the sales history of an item when calculating sales rank.

Takeaways

A few important lessons from these case studies:

1. Never use Amazon sales rank alone as the basis for any assumption about how quickly a book will sell.
2. Books with Amazon Sales Ranks in the millions may have sold more recently than you think.
3. Amazon sales rank is not easily reverse-engineered, and more dynamic that most sellers realize.

-Peter Valley