If only BookBub would advertise my book, would it sell?

My previous post about BookBub concerned the type of ads book bub accepts. In this post I will look at performance, focusing primarily on discounted books in preference to free downloads. Free downloads might have such goals as generating reviews for the book, establishing a fan base for the author, or encouraging readers of the free book to purchase subsequent works in the series. A heavily discounted book might have any of these goals as well, but may also expect to repay advertising costs through increased book sales. BookBub of course cannot guarantee that ads will generate sufficient sales to earn back the costs, but from the analysis below, I think they typically do. I do not herewith endeavor to contradict BookBub’s published sales predictions, but rather to expand upon them.

See the footnote [1] for a few words about the limitations of my methods. Because my estimates of sales are speculative, I only present these estimates to compare factors such as book price, book rating, number of reviews, day of week, ad’s position on the page, etc. So do not consider them for any other purpose than entertainment. In addition to the method limitations mentioned in the footnote, sometimes authors run ads in other media on the same day as the BookBub ad. For example, Amazon has Countdown Deals and Free Promotions that might coincide with a BookBub ad. While this is rare, it could make a particular BookBub ad appear to be much more effective than it would have been alone.

Fifteen books – one day:

Let’s first look at a typical day. Here we see book rank for the first fifteen books on the Latest Deals list for 8/3/2014.

one day of bb

Note: Rank is plotted on a logarithmic scale since ranks here vary from #1 to #119,553. On a linear scale most of the data on the graph would just be clutter at the bottom.

The time axis runs from 04:00 Pacific time on 8/3 through midnight on 8/4. The Latest Deals page typically updates between 05:00 and 06:00 Pacific. Although the ad will disappear by 06:00 on the following day, I continue to track the books’ ranks for the rest of that day.

The free books often change rank before the paid books. This may be because Amazon updates free and paid ranks on a different schedule. Some books respond soon after the ad appears, but most take many hours, usually not until around noon Pacific time. This delay could be due to Amazon’s schedule for updating ranks. The early response of some books may occur because the book is already being promoted elsewhere and is experiencing sales/downloads by the time the BookBub ad goes live.
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My ad was accepted by BookBub! – Should I be excited?

Actually, no. My ad was not accepted by BookBub. The following helps explain why.

BookBub.com is reputed to be one of the best sites for advertising a ebooks. Because of this reputation they are flooded with requests to place ads. Some authors become quite excited when, after applying for months, BookBub finally accepts their ad. For some, the ad does indeed result in a gratifying volume of downloads or sales.

BookBub vets ads carefully and charges prices commensurate with performance. As of July 2014, ad prices, which depend on genre and book price, range from $40/day (a free LGBT book) to $1,600/day (a $2+ mystery novel). They are up front about the results an advertiser might expect, both in downloads (for free books) and purchases, based on genre.

The fact that BookBub knows roughly how much money a book ad will generate for the advertiser explains why ad prices depend both on genre and book price. One may calculate the anticipated royalties from sales using Amazon KDP as a guide. Here I assume the following book prices: <$1 = $0.99, $1-$2 = $2, and $2+ = $3. The following table gives the royalty return on investment (ROI) using ROI  = (royalties – ad price)/(ad-price):

bb ROI per price sheet

For free books, the ROI could be measured in term of downloads per advertising dollar. The average across genres turn out to be about 100/$ or one cent per download.

Some genres and book prices do not seem promising in this simple analysis. It is unlikely, however, that each price point will have the exact number of sales listed. It may well be that a $2.99 book has a substantially lower sales volume than that listed, and that a $0.99 book, higher. That will be addressed in a future post.

The prices within a genre are a simple progression: an ad for a book priced $0.01 to $.99 costs twice as much as an ad for a free book in the same genre, an ad for a $1-$2 book costs three times free, and an ad for a $2+ book costs five times free.

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Made it Ma! Top of the world! – Top 100 Amazon authors

H/T for the title to James Cagney in White Heat.

Note: for background on methods, start reading this thread on Amazon sales data with Scraping the Gorilla – Picking data off of Amazon


Amazon publishes a list of the top 100 authors, which is updated daily – mostly. I did a running sample of this list for a few weeks to get a feel for how that list changes, and with a little sampling of individual authors, perhaps to learn how that list is constructed.

First, let’s look at how that list churns. In the below graph (I apologize for the clutter) we see those authors who have appeared in the top 20 at some point during the 24 days of the sample. You can see a bigger, and possibly more legible, version by clicking on it.

top 100 authors churnNote the pause in updates during 6/8 and 6/9, a weekend. From this I might speculate that the list is manually updated rather than based on an automatic algorithm, and whomever was responsible was off. In the legend they are ordered by the number of days they were in the top 20.

While the top authors plug along well, we can see many authors quickly climb from lower in the list, and almost as quickly descend. I presume this is the result of a sudden and temporary increase in sales. This was not practical for me to verify retroactively – I can evaluate present sales but not past sales unless I were to catalog the rank daily of every one of the thousands of books belonging to all the author in the top 100 list. This would be impolite to Amazon.

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Show Me the Money – What genres are hot.

Note: start reading this thread on Amazon sales data with Scraping the Gorilla – Picking data off of Amazon

UPDATE: The below data is a bit cleaner than the previous data published earlier. This time I was able to collect all best seller lists and the associated 30,000 book pages in a single 24 hour period (6/19-6/20), eliminating most of the motion blur.

Amazon has around 460 fiction categories on five menu levels. The “Level 1” categories I am considering are:

 Science Fiction & Fantasy
 Literature & Fiction
 Mystery, Thriller & Suspense
 Teen & Young Adult

Below these are Levels 2, 3, and sometimes 4 and even Level 5 (Amish Romance, for example, which has less than 100 titles). On Amazon all roads lead to Rome so within Literature & Fiction is a category of Genre Fiction which somewhat duplicates the other four Level 1 categories. I will focus initially on the Level 1 genres above.

The first question that came to mind was, “What genre sells the most?” Unfortunately I cannot answer that, other than looking at the top 100 in each genre. That’s a start.

units sold by genre 201406

Note: See previous posts for caveats and background on how I arrived at these numbers.

Clearly Science Fiction and Fantasy is not as popular as I would like, given that it is my genre. Still, 22,000 books sold each day on Amazon is respectable. So how crowded is the field? Here are the title counts in each of the four genres. ( Including Literature & Fiction on this particular graph would have been misleading because it duplicates so many genre titles and includes categories like criticism and poetry.)

title counts by genre 201406Ouch. SF&F, the smallest category in sales has a huge catalog. Good news for Teen & Young Adult writers though, as they have a big chunk of the sales and relatively fewer titles. Now I have a better feel for who the genre players are.

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Stick With Me, Kid – Is Amazon the Publisher of Choice?

Note: start reading this thread on Amazon sales data with Scraping the Gorilla – Picking data off of Amazon


Much has been written about the merits of indie versus traditional publishing, whether it be with a Big 6 imprint, large press, or small press. While factors such as creative control and royalties push writers to one camp or the other, in actuality very few writers have the luxury of choosing. Those writing for niche markets or with  styles that may not be widely appreciated, may find it difficult to gain the enthusiasm of agents or publishers who are hunting for the next NYT Bestseller. It is, nevertheless, interesting to ponder just how sales differ between the various publishing routes.

To that end I analyzed the 13,000 Kindle titles contained in lists of the top 100 sellers in the 195 subcategories within Amazon’s genre categories of mystery, romance, fantasy & science fiction, and teen & young adult. (Yes, 195 x 100 is 19,500, but many titles appear in more than one list, and some lists have fewer than 100 titles because there are fewer than that number in the subcategory.) Here I use “Big 6” to refer to the various publishing arms of the following six corporations: Hachette, Holtzbrinck/Macmillan, Penguin, HarperCollins, Random House, and Simon & Schuster. These companies comprise over 300 imprints. “Large” is 20 or more authors among the 60,000 titles examined. “Small” refers to a publisher with between 3 and 19 authors . “Self” means that either the publisher has only one author, the author’s name appears in the publisher’s name, or that this author appears to own the publisher’s DBA. The “Unknown” publisher is an imprint for which I could only identify one or two authors. In most cases I imagine these are indie published, and may include an additional pen name. Likewise, some of the “small” presses may be indies with multiple pen names. “Amazon” refers to their twenty or so publishing imprints.

First, let us look at how many titles on these lists are assigned to each publishing category.

titlesClearly indie publishing is a major player here. One might be tempted to think that Amazon is a minor player. When one looks at units sold, however, Amazon takes on a larger stature. Below is the total number of units sold per day by the different publishers. Amazon has managed to sell a disproportionate share given the few titles it represents. Continue reading


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Sic Transit Gloria Mundi – The Fate of Classic SF

Note: start reading this thread on Amazon sales data with Scraping the Gorilla – Picking data off of Amazon


In a previous post I looked at a few top selling titles. Here I turn to authors, both current best sellers and renowned science fiction authors with a corpus of older, respected works. There is also a third category of indie authors who have been forthcoming about their success by indicating total sales. It is interesting to compare their long term sales with present estimated sales.

First, the current hot genre authors.  (See previous post for caveats.)

Veronica RothBig 624,614$33,122 4.3Y
Nora RobertsBig 67,968$10,159 4.2M/R/F
George R. R. MartinBig 65,408$9,809 4.1F/Y
John GreenBig 68,787$9,380 4.5Y
James PattersonBig 66,633$8,685 4.0M/R/F/Y
Terri OsburnAmazon4,124$7,141 4.3R
Donna TarttBig 64,553$6,983 3.6M/
Harlan CobenBig 63,811$6,788 4.1M/R/Y
Johnny ShawAmazon3,548$5,968 4.2M
David BaldacciBig 63,875$5,037 3.9M/R
Lee ChildBig 64,343$4,905 3.7M/R
Mary Higgins ClarkBig 62,830$4,838 4.0M
Stephen KingBig 63,304$4,038 4.2M/F
Liane MoriartyBig 63,469$4,024 4.5M
Janet EvanovichBig 62,730$4,003 4.0M/R
Jessie HumphriesAmazon2,285$3,990 4.3M/Y
James DashnerBig 63,323$3,585 4.3Y
Rick RiordanBig 62,104$3,455 4.5F
Suzanne CollinsBig 62,672$3,439 4.6Y
Debbie MacomberBig 62,538$3,203 4.4R
John SandfordBig 61,709$3,112 4.0M/R
Dr. SeussBig 62,937$3,083 4.6Y
Cassandra ClareBig 62,545$2,942 4.5Y
Stuart WoodsBig 61,740$2,928 3.8M/R
Gillian FlynnBig 62,333$2,841 3.8M
Daniel SilvaBig 61,342$2,599 4.2M/R
John GrishamBig 62,636$2,491 3.8M/R
Diana GabaldonBig 62,386$2,464 4.3R/F
J. S. CooperSelf2,262$2,398 4.3R

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Scraping the Gorilla – Picking data off of Amazon

Note: this is the first in a series of posts on Amazon sales data as gleaned from the Amazon website.


There is little doubt that indie* publishing has given upcoming writers new options. They now can choose not to battle gatekeepers at publishing houses, or accept the onerous publisher contracts with their low royalties and rigid publishing schedules. Whether indie publishing is inconveniencing the Big 6** publishing houses is debated. That debate requires data, which publishing companies are loathe to reveal. Some of this data can, however, be gleaned from the 500 pound gorilla in book retail: Amazon.

Some questions that such data might answer:

  • How often do indie published titles earn royalties comparable to those of Big 6 titles?
  • How many indie authors earn royalty incomes rivaling those of Big 6 authors?
  • How many authors can make a living from their writing?
  • What are the relative sales in each genre/subgenre?
  • How important are online customer reviews/ratings to midlist sales?
  • Do series outperform standalone titles?

To answer these and other questions, I set out to scrape gather data from Amazon’s website. There had been discussions on the internet (ex: kboards.com) about what Amazon’s book rank means in terms of sales. Many authors have posted their rank vs sales figures, which helps to roughly deduce sales from rank.

Early on, I discovered authorearnings.com, a project led by the much admired and successful indie author Hugh Howey. This project sought many of the same answers and published not only reports on project findings, but the raw (although anonymized) data on individual titles. Data mining has always fascinated me, and one thing I’ve learned from many years of analysis is how data can be tortured into confessing – confirmation bias. I wanted to analyze the data myself so carried on writing scripts to pull and parse pages on around 60,000 titles. This included the top 100 titles in the various fiction categories (there are over 400 categories), as well as the complete corpus of around 200 authors that included the 100 top ranked Amazon authors, authors on NPR’s 100 best SF list, and around 20 indie authors known to have enjoyed success. Although I am an indie myself, I did not set out to make a point about indie publishing.

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