Book Amazon sales data for books about TMS

Hi everyone,

I've been gathering book sales data for books about TMS recently, and I thought that I would share what I've found.

Amazon lists roughly 32 million books on its site and it publishes a "Sales Rank" for most of them. I've created a list of books about psychosomatic pain that allows us to compare the Amazon sales ranks of the different books. I wanted to make the most comprehensive and helpful list I could, so I used data from Amazon to include all books about psychosomatic pain (or equivalents) that tend to be bought by people who by other TMS books.

The largest factor determining Sales Rank is the amount of time since the last sale. Because of this, Amazon sales rank can fluctuate significantly, based on whether the book had a good day or a bad one.

For each book, the list includes different entries for hardcover, paperback, mass market paperback, and kindle editions, depending on how many editions are available.

By watching the fluctuations in the official sales rank, the list is able to calculate an estimate of how many books are sold per month. I've been updating the list since late June, so the July sales estimates are probably pretty good. However, since I didn't start until late June, the June sales figures should be ignored as they are incomplete.

Because Amazon lists approximately 32 million books on its site, any book with a sales rank of over 16 million can be considered "above average." By that measure, TMS books are doing exceptionally well.

I hope people find the list to be interesting and helpful. If you have any questions, please just let me know!

http://www.novelrank.com/user/forestfortreestms

 

I've received a couple of questions about how the estimates of monthly Amazon.com sales are calculated. Amazon does not release figures on monthly sales for books, so the numbers must be estimated. In the following video I explain my understanding of how this is done:

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The numbers aren't perfect, but I'm glad we have them.

 

Unfortunately, the program doesn't allow for tracking anything else but paper and Kindle editions of books. At some point I hope to look for alternatives for audiobooks, and if I find any, I'll add them to my first post.

I don't know if Amazon factors sales of used books or Amazon Marketplace sales into their Sales Rank. That's a very interesting question, though, and I'd be love to hear if anyone can figure that out.

I wonder if what you are saying is captured in the idea that book sales follow a power law. I don't want to hijack this thread with a discussion of Power Laws, though, as the subject is very mathematical and therefore not of interest to most people. Therefore, I've started a new thread to reply:
http://www.tmswiki.org/forum/threads/amazon-sales-rank-book-sales-and-power-law-distributions.5145/

If you would like to continue this discussion, please reply to that thread rather than this one.