Monthly Archives: August 2014

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. 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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