Understanding Amazon’s New Algorithms Is As Easy As ABC Publishing

Amazon’s KDP Select introduced a new tranche of self-publishers to the upper reaches of the charts for the first time. For the first couple of months of this year, a new seam had been discovered in this self-publishing “gold-rush.”

It didn’t last too long, however. By the end of March, even those newly minted authors were openly considering leaving KDP Select, despite how successful it had been for them. Self-publishers were noticing that even when they had a stellar free run, garnering thousands and thousands of downloads, it was no longer catapulting them up the charts on their return to the paid side.

Science fiction and fantasy author Ed Robertson penned an excellent hypothesis and gave me permission to re-post. If you don’t understand exactly why successful free runs used to almost always translate into a run at the charts, then read my post on Popularity Lists first for background. That said, here’s Ed:


Around March 19, Amazon changed the way they sell books. In a Kindleboards thread devoted to the subject, authors tracking the performance of books during and after a free promotion began reporting strange results. Prior to then, books that gave away several thousand copies during a promo would shoot to the top of the popularity lists some 36-48 hours later. It was like clockwork. Clockwork that paid you several hundred dollars.

Because the popularity lists are a big deal. These are the default book listings you’ll see when you’re browsing around by genre. Here’s the Fantasy list, for instance, with GRRM clogging up the top 10 like the greedy goose he is. If you could ride a free promotion to the top of those lists, your book would be extremely visible to shoppers. Depending on genre and your book’s presentation, topping the pop lists could snag you dozens or hundreds of sales before other books overtook you. Sometimes that visibility was enough to launch a book into the stratosphere, where the stratosphere is also made of money. It was kind of a big deal.

Then, things changed. Except they didn’t change. Not for everyone. Authors began reporting lower sales than expected as well as strange-looking lists. Chaos reigned! Dogs and cats living together, watching couch-bound authors tear out their hair. After a couple weeks, we thought we had it figured out: there was no longer a single popularity list. There were two, and books no longer seemed to be vaulting to the top no matter how many free copies they gave away.

Well, we were wrong. There weren’t two lists. There were three.

Because I am extremely imaginative, I’m going to refer to them from here on out as List A, List B, and List C. I’ll get into the methodology in a bit, but for now, I worked this out through carefully observing my books, reading other Kindleboard authors’ results obsessively, and lobbing theories around with other authors. I would never have figured this out on my own. I know, never say never. Trust me, eventually I would have gotten frustrated and left to play Mario Kart instead. One other author in particular did tremendous heavy lifting. Like the Eye of Sauron, he (or she?!) is far-seeing and awesomely powerful. And much like Sauron, you can’t invoke his or her name without facing terrible wrath. Some of the Eye’s secrets must remain just that.

But the outcome of that info can be revealed. So without further ado, here’s how the three lists work.


List A is the same version of the pop lists that existed prior to March 19. It is Select- and freebie-friendly. Here’s roughly how it works:

  • Ranks are heavily weighted to the last few days
  • Free book downloads are weighted equally with paid sales
  • Borrows count as sales

List B appears to be a throwback pop list, one that was running throughout most of last year. Here’s how book ranks are calculated on it:

  • Ranks are determined by the last 30 days of sales, with no extra weight given to the most recent sales
  • Free book downloads are discounted heavily–maybe as little as 10% the value of paid sales
  • Borrows don’t count as sales

List C is a lot like List B, with a couple major differences:

  • Free book downloads aren’t counted at all
  • Recent sales are weighted somewhat more heavily than List B(?)
  • Borrows don’t count as sales

What does that mean in practice? A lot. A lot a lot a lot. Here’s where my book The White Tree ranks on all three lists at this moment in time. Each shot will look a bit different because they’re taken from different browsers–that’s one way to see different lists. The list in question is Fiction > Fantasy > Series, a fairly quiet little fantasy subcategory.

List A:

List B:

List C:

Pictured: Oh shiiiiii–


Most of this was achieved through comparing tons and tons of different books on different browsers, just like the screenshots above. Here’s some stats for the book in question that helped me figure out what was happening here. On March 28-29, The White Tree was downloaded 4700 times (free). On April 17, it was downloaded an additional 1300 times. In April, its paid numbers came in at 210 sales and 46 borrows.

Since March 19, my main browser’s been displaying List B. My big clue to List B came on April 28, when I noticed my book had, over the span of a day or two, dropped from #67 in Epic Fantasy to #165. Rank didn’t slide–it instantly dropped off a cliff. Why? Because it had been 30 days since all those free downloads had come in. I’d noticed the same thing around March 23–I’d done a huge giveaway February 22-23, and once 30 days elapsed, it suddenly plummeted from around #45 to around #255. I didn’t know what it meant then, in fact I don’t think I even knew there were two lists at that point (let alone three), but when it happened again, I had a pattern.

I also had several weeks of observations piled up by then to help me understand new data. For weeks, List B had been showing me very static lists. The books at the stop stayed at the top. There was very little churn. There were very few Select books, i.e. books that were likely to have recently been free, especially within the top ~60 results (first five pages). Most books at the top were traditionally published. List C was even more trad-dominated; generally speaking, an indie title on List B would be ranked 15-25% worse on List C if that title hadn’t been free, and would rank much, much worse if their List B rank was dependent on free downloads (like, hundreds of places).

When I compared the top 240 titles in Epic Fantasy between List B and List C, here’s what I found: on List B, 188 titles weren’t in Select, and 52 were. On List C, 217 titles weren’t in Select, and just 23 were. With no benefit from freebies, and with fewer paperback sales to pad the numbers, most indies get killed in List C.

When it came to figuring out that borrows weren’t counted in List B and C, The Eye of Sauron was particularly helpful. We compared Select books with lots of borrows to non-Select books whose sales were roughly equivalent to the Select books’ total sales+borrows. On List B and C, the non-Select book came out ahead by a good chunk. We compared Select books with lots of borrows relative to sales with Select books with few borrows : sales. (None of these books had recently been free, which acted as a “control” between List A and B.) The ones with a higher ratio of sales : borrows almost always came out better on List B than on List A.

While I wouldn’t lay my life on the line for every one of these observations, I am very confident in the overall conclusions reached. There are three different lists. You can see them for yourself–just compare lists on different browsers, computers, and Kindles. If you’ve gone free recently, you’ll note your popularity rank on List A is much better than B or C.

How do you tell which list you’re looking at? Well, that could take a day or three to figure out, but in short, if you see a bunch of Select titles on the first pages of the pop lists, you’ve probably got List A. If it’s almost all traditionally published books, it’s List B or C. From there, compare your lists on another browser/device; if you’re seeing List C, trad books will generally be even more dominant.


What does all this mean? Hey, maybe you haven’t noticed, but this post is already epically long. The internet is only so big, you know. I’ll save that for a future post. For now, here’s what’s key: there are three different lists. Your book is listed on all three, but any given shopper is only seeing one version of the lists. (In other words, different people see different lists.) If you’re an indie in Select, one of these lists is good. The other two? Well, let’s just hope they’re not here for too much longer.

UPDATE: The same day I posted this, Amazon changed their sales algorithms again. This post will provide a lot of the background to what I talk about in the followup post.

* * *

I want to thank Ed for allowing me to re-post this. His blog is excellent, and particularly strong on things like understanding the inner workings of Amazon.

If you would like to check out some of his books, the fantasy novel The White Tree (pictured up top) is particularly recommended and available on Amazon and Amazon UK, but he has plenty more titles here.

I can also vouch for his data geek bona fides and the methodology employed above. We’re part of the same online writers group and I watched the testing of this theory unfold as it was verified by multiple participants.

While the implications of some of this may seem ominous for self-publishers – especially those depending on the power of Select and the associated free runs – I want to urge everyone not to panic, and to keep speculation from veering into tin-foil hat territory.

Amazon is always testing things, making frequent changes to their algorithms. Some of those changes have favored self-publishers, others haven’t. As I have said on many occasions, Amazon don’t care who has published a book, and have previously made changes that disfavor books from their own imprints.

What they do care about is recommending the book the customer is most likely to purchase. And the basic equation never changes: write good books and lots of them, and let readers know they are there.

Speaking of good books, Ed Robertson’s dystopian novel Breakers is free today.

UK peeps can grab a free copy here.

One final thing (apologies to Ed). I’m blown away by the response to my open letter to the DOJ. I was expected a handful of writers to co-sign, tops. There must be around 150 names now. So, a big thank you from me. I’m going to keep it open for another day or so as names are still pouring in.

Then it gets sent.

UPDATE: Ed’s Breakers is #8 in the free store. Go Ed!

David Gaughran

Born in Ireland, he now lives in a little fishing village in Portugal, although this hasn’t increased the time he spends outside. He writes fiction under another name, has helped thousands of authors build a readership, and has created marketing campaigns for some of the biggest self-publishers on the planet. Friend to all dogs.

46 Replies to “Understanding Amazon’s New Algorithms Is As Easy As ABC”

  1. David : All that info is great and understandable. But how does one get the word out if the big distributors – Amazon;Barnes and Noble; and Ingram do not put your book http://bit.ly/I1bCME as a New Release or in book’s genre. In this case True Crime/Autobiography?

  2. I was reading a piece in Wired magazine recently about how companies are almost always split testing now. It used to be you might split test every now and then before you were going to change your homepage or something. Some people would see website A and a smaller group would see website B, and data would be collected to determine which website performed better, and then the company would redesign the main website for all users.

    But now companies are in an almost perpetual stage of split testing, serving up different pages loaded with different content to see what works best. It’s all about the data. This isn’t just content sites, but sites that sell to us.

    I have little doubt that Amazon is doing the same thing. And this explains the different lists that we see.

    1. One thing I’ve noticed is that amazon seems to roll out changes, perhaps to different servers or perhaps because of split testing, so depending on what server you get you will get slightly different pages.
      I first noticed this when they started to put the estimated print page count on kindle book pages. When they first implemented this sometimes I would get a page count and other times I wouldn’t, but now I get it every time.
      And I’ve seen it a couple of times since.

  3. If Amazon is split-testing, then I’d say the method which ultimately gets parsed to the most users will be the one which results in more sales. Perhaps they weigh in keeping KDP Select exclusives a bit into the math, I dunno. But ultimately, your advice to not worry is correct. Amazon will do what’s best for Amazon. And so far, what has been best for Amazon is married with our own goals as indie publishers on the platform.

  4. Split tests is just what we were thinking was happening here, David W. The interesting thing, though, is they recently changed their algorithms again to condense the split lists to a single list (http://www.edwardwrobertson.com/2012/05/amazons-ever-changing-algorithms-part-2.html). The new version borrows elements from List B and C. The specifics of what they brought from each list might help us understand how Amazon conceives of the ebook market at this stage in its growth.

  5. You know, I’ve been working on the Internet for over 15-years now, and it’s funny to see how things keep repeating themselves. We all scrambled (we still do) to figure out how to “rank” well on Google. For a time, before the Florida update way back when, it was super easy to do too. I could get to the top of Google in sometimes less than an hour for a very competitive term. Of course, back then, there wasn’t that many people creating content or jockeying for position. But then Google got smart and changed things and made it hard and now it’s a billion dollar business (seo firms).

    Amazon didn’t’ make the same mistake. Why? Because their system isn’t based on “relevance” like Google’s is/was, it’s based on cashola/sales. My point is, trying to figure out how Amazon ranks books is a fun topic to read about, but in all honesty, there’s never going to be a credible “Amazon ranking procedure” for people to follow. Sure, write a great book and title it right and add tags and get reviews and try free promo days and wash, rinse, repeat. All that stuff is important.

    But at the end of the day, I really believe that if an author wants to sell a lot of books they are going to have to do it themselves, on their own platform. There simply is NO WAY around this inevitable fact Neo.

    Great analysis in this post. I just don’t think it really makes a difference to you/me and other authors. Amazon will never be “gameable”, which in all honest truth is why we have these conversations… to find out how to beat the system. I don’t think it’s going to be possible, unless you get lucky.

  6. Thanks Ed and Dave. Very interesting. I have one question, which may have been asked already in the comments. What governs which list is displayed. You talk about different browsers but don’t explain. For example, does Amazon send list A to all IE browsers and B to Chrome? That would be odd. Have you noticed any pattern here. I’d have thought it more likely that Amazon presents you with List X based on your Amazon profile or purchasing history.

    All fascinating stuff.

  7. Well, the lists were recently condensed to a single one–List D, I suppose–so this is more of a retrospective, as well as the foundation for understanding the modified list that replaced them.

    That said, I don’t really know how Amazon was choosing to distribute the ABC lists. It seemed fairly random and even. It also seemed like if you went to Amazon using a clean browser without any history, cookies, etc., it was more likely to display List C.

    But I wouldn’t want to state even that much as fact. We only had a population of about 8 authors working on this running 2-3 browsers apiece. In terms of how often and to whom Amazon was displaying the lists, then, that sample size is really just too small to have any confidence in.

  8. Ed, as always, you’re a mensch. This was a terrific, disheartening read. Like, I’m never putting a book in Select again. o_O My alsobots have still not recovered, to the point I’m considering not using the other three free days I have left on my one book in Select.

  9. I agree with Paul Dillon–I’d love to know which browsers are more likely to get which lists. But I suppose if you figured that out, it would all change tomorrow anyway. I find this all a little scary. We writers need to remember that Amazon is a big, soulless corporation just like the Big 6, and even though they’ve been indie author-friendly for a while, we’d be naive to think that’s going to go on forever.

  10. Excellent job Ed and Eye of Sauron. For me, you simplified a complicated subject so I can understand and learn from your findings.

    David congrats on the response to your letter.

  11. Fascinating, along with the Part 2 article. If free doesn’t buy visibility, the suggestion is that, at least, we are getting our books into the hands of thousands of readers. The follow-up question is how many will read all the free books they have filled their Kindles with? And when? Indie publishing remains a marathon. A positive over traditional publishing where the author who doesn’t earn out fast enough is shunted to the side.

  12. Thanks and thanks to Ed, Ms. “Eye” — I like to think of her as a woman. With a little bit of mascara to show off her lovely eye, and Dave. (Not that her mascara would show off Dave… I need an editor here… I don’t even think Dave wears mascara. Very often.) This post explains a lot, including the brief but incredible run I got beginning 12/26/11 just after going off a freebie KDP Select day back when it was brand new territory. Thousands of dollars in a week — perhaps I stumbled on the best week ever. I have made just about that much again, now, but it took nearly five months to equal that single week’s profits. Oh the roller coaster life of an indie writer!

    Patrice Fitzgerald, author best-selling Kindle thriller RUNNING

  13. Amazon is in the business of selling books, among other things, and free books don’t make them any money. I think their program was more successful than they anticipated, in as far as offering the free days went. Yes, the free offerings drive traffic to the site, but what are those people doing? If you look at the “also boughts” on my book that is price matched free, they are simply downloading free books and moving on. That, combined with all the extra customer service hours spent dealing with upset authors whose free days didn’t start/end at the right time, etc. and I think you have much of your answer for why they made changes to the algorithms. They’ve priced the Kindles in such a way that they barely make any money (if any at all) on the devices, according to studies of the manufacturing costs, in order to profit on content. If people are largely only downloading free content, however, that puts them in a precarious position.

    Yes, people purchased books after they came off free days, but I’d be willing to bet those people were there to spend money regardless. The “fresh-off-free” books simply caught their eyes because of the list.

    So, it’s not that Amazon is pro-indie, or pro-trad; it’s that they want to disengage from some of the headaches that the Select free days have caused by making them less attractive. Just my .02.

  14. I actually posted about this topic today as well. I’ve re-signed for one more period and then all options are on the table. KDP Select was an experiment for me in any case.

  15. Reblogged this on Sailing the Void and commented:
    Guest post from Edward W. Robertson via David Gaughran. I’m barely coming to grips with the idea of a Popularity List vs. a Bestseller List, and now there are three?!


  16. Good info, David. Of course, the real problem is that Amazon uses the only matrix that is important – how much money they make in sales. I am not saying it’s bad – it actually makes them better than pretty much any other marketplace. It’s just a pain in the lower quarters for the rest of us whenever they start changing things based on that matrix.

  17. I did not understand a lot of this, David, but I am not buying this Amazon = indie interests stuff at all. I am about to put two books on Select but I get the feeling I am due for a right royal screwing.
    Three lists = deception, in my book..

    1. I don’t think I ever said that Amazon = indie interests. I think it’s quite clear that Amazon = customer experience. I suspect that they felt that the boost from Select was a little too powerful and they wanted to temper it somewhat. Split testing such as these three lists is very common in tech companies. Google do it all the time. It makes sense to test out a feature and see the results before rolling it out site-wide.

      As to whether this is something in the “Con” column of Select – yes, that would be my opinion. But I wouldn’t consider it a dealbreaker. If I was about to release a book, I might *maybe* hold off myself and watch how other people’s free runs (and borrows) go over the next couple of weeks. There are some excellent threads (look for the MEGA one) on Kindleboards tracking all this stuff.

      1. David, you said “Split testing such as these three lists is very common in tech companies. Google do it all the time. It makes sense to test out a feature and see the results before rolling it out site-wide.”

        So true. I’m guessing that Amazon will use the results to determine two things:
        1. Profit
        2. Market growth

        Amazon cares deeply about both. By having 3 lists, they can weigh factors that creates their optimum (trade off between profit and growth).

        Sucks to impact indie-authors so much. But Amazon is a business and they aren’t here for indie authors. I suspect this could be a long term study. For who cares is short term sales go up at the expense of long term sales? Amazon will know something no one else does and that will let them keep growing.

        But if Select was ‘too powerful’ and was turning off customers, than it is best Amazon reacts.


  18. Thanks for explaining this. I personally noticed that my post free sales runs dropped, and where I had been seeing an increase in sales of other books as well as the freebies, that dropped too. Before I let the select expire, it got to the point that I wasn’t getting any sales on books on select, just lots of downloads. I think a lot of shoppers have the opinion that if a books on select they can just wait for it to be free. Just my own experiences.

  19. I believe many people discount some of the other side goals of Amazon–for example, the Prime program, which I’ve always felt was the main impetus for Select. Select served not only to bring 130,000 books exclusively to Kindle, but it also gave the Prime library the illusion of depth. Of course, that wasn’t necessarily the 130,000 books that readers wanted, but I believe Amazon is committed to Prime for the long term.

    Select will still have value. I don’t know any experienced indie who assumed the freebie bit was going to be good for more than one 90-day term, with some possible momentum in the second 90 days. But instead of “Woe is us, Amazon is hating indies,” look at how many tools are still easily available and freely offered by Amazon. Amazon owes no one anything, and we all knew a house cleaning was coming. Thanks for the post.

  20. In your opinion, is there a way to really launch into the stratosphere if you self publish. By that I mean, get movie deals for your book. I guess you would have to get a Hollywood agent, or some kind of contract handler different than a literary agent, but yeah, that is my question. Thanks!

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  23. Hey David thanks for the wonderful post. I honestly think the KDP Select program has lost it’s luster. I am very thankful to the last free promotion I ran but I did so in conjunction with the Free ParTay and I know without doubt it was that effort that catapulted my Tears of Crimson Vampire series into a bestselling Gothic title. In the end it’s all about promotion. Fortunately I had a series and the first giveaway which resulted in 12,000 free books pushed on to my second book and I actually was able to profit.

    I have one book left in that program and I’m waiting impatiently for it to come out. I’ve been missing sales at B&N which was easily proven when I loaded my first book there. Bottom line to me is promote your books to the biggest audience you can. It was great while it lasted and I’m so glad it’s over LOL

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