Tag Archives: sales rank

Why Does NovelRank Underestimate Sales for Popular Books?

Every once in a while, I get an email from an author with Kindle Direct Publishing (KDP) access who wonders why their numbers are different between NovelRank and KDP. First and foremost, let me say that if you have KDP access for your titles, that is the most accurate source of sales data. Secondly, remember that NovelRank estimates sales based off of sales rank, which is also a data point provided by Amazon, a priority system for ranking books based upon their sales. This makes any estimates vulnerable to many variables, and I wanted to provide some additional info for folks.

One final note before I start listing things: I created NovelRank as a resource that allows authors to spend less time reloading webpages, spend more time writing, and get a feel for the effectiveness of marketing campaigns by seeing hourly and daily fluctuations. It’s hard to communicate this throughout the website, and a few folks have taken to disliking NovelRank strictly based on sales estimates. It hurts a little, but I try and focus on those who are benefiting from the service.

Causes for Underestimation:

  • The better the sales rank, the less variation. Since sales estimates are based upon changes in sales rank, this reduced variation is the first source of underestimation.
  • Furthermore, when sales rank is really good (low number), improving estimates usually means adding arbitrary +X amounts to sales estimates. I try and avoid this as it amounts to guessing.
  • The algorithm uses the last 1000 data points to not only identify sales, but also try and throw out false positives (when sales rank changes a small amount not due to sales but due to Amazon adjusting the ‘list’ of books being ranked in that category). This is typically a boon, but in some cases this can miss genuine sales.
  • If Amazon fails to update sales rank for that hour (common occurrence), that data is ‘lost’, because if a sale occurs during that time, by the time a new sales rank is presented, there is less differentiation.
  • Multiple sales on an individual order are represented as 1 sale by sales rank. See this post about Sales Rank Myths for more info.
  • Finally, sales rank is an ever changing secret formula which NovelRank’s algorithm is constantly trying to learn from. It will never be perfect, but I always hope it can keep up.

I hope this clarifies things for new authors. NovelRank exists so you can do more writing, selling, and living, so enjoy!

Amazon.it (Italy) Sales Rank Tracking Now Available

As of earlier this week, Amazon released the Product Advertising API for Amazon.it, Italy. Within a few hours, NovelRank was enabled for tracking sales rank on Amazon.it. If you want to add your book for tracking, just repeat the process you used when first adding your book: Copy and paste the Amazon link (can be from any Amazon domain, doesn’t have to be the Amazon.it link) into the Sales Rank tracking page. Make sure you check ‘Add Additional Domains’, and click the track button to finish the process. Within a few seconds, all of Amazon’s domains will be checked to see if updates for tracking are available. Enjoy!

Sales Rank Check Frequency Changes – Growing Pains

Starting today, a new structure has been put in place to ensure the longevity and speed of NovelRank continuing through year two and beyond. This is based on the frequency that NovelRank will check the sales rank for a particular book on a particular domain (.com, .de, .co.uk, etc.). I thought long and hard about this, especially as an author who sells from 1 to 10 books a month in some cases, and I think this will be valuable and fair to everyone.

Here is the breakdown:

  • If a book has been sold in the last 7 days on a specific domain, it will continue to have its salesrank checked hourly.
  • If a book has been sold in the last 14 days (but not the last 7), the checks will occur every 4 hours.
  • If a book has been sold in the last month (but not the last 14 days) on a specific domain, the checks will occur every 8 hours.
  • If a book has not been sold in the last month on a specific domain, the check will occur once per day.

It’s important to note that as soon as a sale is made, the clock is reset and the book goes back to hourly salesrank checks! It is also domain specific, so in the case of some books (see my PHP book for example), it will check .com hourly, but .fr and .ca would be daily, thus it will vary between domains even within the same book, as many books are popular only in specific regions.

But WHY?

Two big reasons:

  • Less frequent checks allow the system overall to be faster at loading pages and data (more improvements coming soon on this)
  • More capacity for NovelRank to support tracking a larger number of books and benefiting more authors going forward. Amazon has limits on the amount of data you can request per second, so there is a raw limit to what NovelRank can provide due to these restrictions by Amazon.

I want NovelRank to always be useful, fast, and benefit as many authors as possible, and this is just the first step in continuing to uphold these goals. This slow down for books that are not actively selling but actively being tracked will be gradual and be in full effect by April 6, 2011.

What about new books?

When a book is first added to NovelRank for salesrank tracking, its last sale date is set to the day the book was added, so it will immediately be treated to hourly sales rank checks for at least the next 7 days (more if it continues to sell books!).

Final Word

When I use the term books here, I am referring to any paperback, comic, hardcover, kindle, etc. format that is tracked on NovelRank. For simplicity I just refer to everything allowed on NovelRank for tracking as books. The FAQ has also been updated to reflect this change. Photo courtesy of digitalmums.

Sales Rank Myths Busted – What Effects Changes in SalesRank

what does sales rank mean It’s time to put myths, legends, and mysteries to rest. Sales rank has been elusive for too long, so thanks to the support of NovelRank donations, I’ve conducted a series of tests to answer some long standing questions about this elusive beast we call, Amazon’s Sales Rank!

MYTH: Sales rank improves when a review is added.

Reality: False. Testing reviews, verified purchases as well as unverified reviews had no effect on a book’s sales rank. This is false for anything except actual sales which do effect sales rank.

MYTH: Sales Rank automatically returns to original value when a kindle book is returned.

Reality: False. This was tested by purchasing a Kindle book at 5:47am. at 8am, Amazon reflected the new sales rank. At 8:30am, customer support was contacted and the e-book was returned. Sales rank deteriorated normally and did not reset back to the original pre-sale value.

MYTH: Book purchases effect sales rank immediately.

Reality: False. There is a 3 hour delay between when a purchase is completed and when the sales rank is reflected by Amazon. This ensures that the order will not be canceled (they are fast). This is true for both Kindle and print purchases.

MYTH: Purchases that are affiliate driven (Amazon pays a percentage of the price to the affiliate referrer) do not effect sales rank.

Reality: False. There is no difference to Amazon between an affiliate sales and a sale driven by Amazon.com direct searches. To them, a sale is a sale is a sale is a… you get the idea.


The above image began with “fairy tale map” by angelic0devil6, Creative Commons: Attribution license.

MYTH: Purchasing multiple copies on a single order does not improve sales rank like purchases made on two separate orders.

Reality: True! To perform this test, I purchased three different books within a single order. One was a control (single copy), one had two copies purchased in a single order, and the last had a single copy purchased. After submitting that order, using the same Amazon account, 10 minutes later I purchased a second copy of the 3rd book (which had a single copy purchased in the first order). The results? After 3 hours, all 3 books moved from a rank of 1,020,000 (+/- 14,000) to a rank of 123,500 (+/- 500). After 1 additional hour, the 3rd book moved to a rank of 64,000, reflecting the second purchase order!

MYTH: A canceled order will cancel the sales rank effect.

Reality: True. Purchasing a copy of a print book and then canceling the order 20 minutes later (while still allowed by Amazon) will not trigger a change in sales rank.

Final Thoughts

I hope everyone enjoyed this insight. If you have any myths you’ve always wanted busted, put them in the comments below. This is one of those tests I wanted to do for a long time, so I’m glad to finally get this information into the hands of authors. Basically, increase sales, and if possible, have them all happen at the same time using separate orders on Amazon to ensure the largest effect on sales rank! Make sure to use the links below to share this post with your fans and fellow authors.

Finally, thanks for using NovelRank and thank you to the supporters whose donations made this possible!