Anatomy of a Countdown Promotion

I recently completed a Countdown Promotion in on Kindle Select.

Before the promotion my book (The Black Orchestra) was priced at $3.99 and selling at a rate of 4 books per day on The promotion ran as follows (times are GMT):

Noon Dec 6 to noon Dec 8 selling price 99c = 0.25 of the usual price

Noon Dec 8 to noon Dec 10 selling price $1.99 = 0.5 of the usual price

Noon Dec 10 to noon Dec 12 selling price $2.99 = 0.75 of the usual price

I expected the volume of sales to be influenced by the selling price, but I was amazed at how predictable this relationship turned out to be.

The royalty from each stage was constant.

In mathematical terms, this can be expressed as follows:

 N*d = M*D

where N is the number of books sold per day, d in the discount selling price, M is a (constant) “Magnification factor” and D is the number of books sold per day before the promotion started.

We can adjust the formula to give the number of books sold at each increment:

N = M*D/d

Applying this formula to the three stages of the promotion, we get:

N(1) = M*D/0.25

N(2) = M*D/0.5

N(3) = M*D/0.75

In the case of my book, D = 4 and (based on sales at increment 1) M turned out to be 7. Predicted sales, based on the formula are:

N(1) = 7*4/0.25 = 112

N(2) = 7*4/0.5   =   56

N(3) = 7*4/0.75 =   37

The promotion for each increment ran for 2 days, giving predicted sales of

224 + 112 + 74 = 410

Actual sales were: 

225 + 109 + 86 = 420

Sales for each increment continued beyond the cut-off. I can only suppose that the data was being collated manually. The last sale in the last increment was recorded close to midnight (GMT) on 12 December, 12 hours after the promotion had ended.

The “Magnification factor”, M obviously depends on the amount of publicity given to the promotion. In my case, I used twitter and a friend gave it some twitter exposure as well. I also put notices on a number of Facebook sites that welcome these sorts of notices (thanks to Mary Louisa Locke for these). I paid no one to help advertise the promotion.

The Amazon ranking, which stood at 26,000 before the promotion, dropped (ie rose) to 1,350 and fell away again. At the end of the promotion, the ranking was 2,500.

The total predicted royalty income from the promotion is easy to calculate:


The normal effective royalty rate, R is $2.3 (70% of $3.99 in US and some other countries, 35% in other countries).

6*D*M*R = 6*4*7*$2.3 = $386

The actual income was higher, as the sales figures exceeded the predictions.

The expected average royalty per book over the whole promotion is independent of D and M and depends only on the discount increments:

3*$2.3/(4+2+4/3) = $0.94

The actual average royalty per book was slightly above $1.09

The expected income in the absence of the promotion would have been 6*D*$2.3 = $55, so the predicted gain from the promotion was $386 – $55 = $331. The real gain, of course, is 400 new readers and maybe some new reviews.

The promotion also generated about 20 borrows on KDP Select at $2.40 each.

It would be interesting to compare these results with the experiences of others to see if my formula holds up for other books and to examine the effect on the “Magnification” factor of increased publicity.

Any volunteers?


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How Do Ratings Work?

Since August 19 I have been recording Amazon UK sales and rating figures for my book The Black Orchestra. That’s numbers for 65 days. It struck me that the ratings on Amazon UK are not as responsive as the equivalent. The ratings in the UK seem to be updated less regularly — maybe every couple of hours. I have seen sudden small late afternoon spikes in sales (I’m talking 2 or 3 books, here) that aren’t reflected in the ratings until close to midnight.

I was puzzled by the way the ratings seem to react to small fluctuations in sales, which suggested that the relationship between sales and ratings is a short-term one. My best guess was that this relationship was based on no more than 2 days’ sales.

I decided to check this out, using MS-Excel’s CORREL function, that produces a correlation coefficient  for sets of numbers taken in pairs. Here’s what I found:

1 day coefficient: -0.54

2 day coefficient -0.72

3 day coefficient -0.69

4 day coefficient -0.67

5 day coefficient -0.65

6 day coefficient -0.68

7 day coefficient -0.68

10 day coefficient -0.61

14 day coefficient -0.43

30 day coefficient +0.12

These figures tell me that, as I suspected, the ratings are most strongly correlated with the 2-day sales figures, and bear no relationship at all to the 30-day sales figures.

Notes: The sales figures used in these calculations exclude KOLL sales. However, I don’t think they would have made much difference to the result if I had recorded and included them.

Total sales for the period of the study: 229 (KOLL figures for the period: 6)

Highest : lowest rating achieved during the period: 4,592 : 27,061

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How to Choose Character Names

Writers – Writing Tip #11

This is the eleventh of 12 posts for writers who are planning to self-publish using the great services now available to the amateur writer, such as Smashwords, Amazon KDP, CreateSpace etc.

11. How to Choose Character Names

Choosing names for your characters can be difficult. The best approach seems to be to keep a list of your character (first and second) names and make sure they start with different letters of the alphabet. Think of Holmes, Watson, Lestrade and Moriarty.

There’s more to it than that, though. It seems readers have difficulty distinguishing similar names: Melissa and Matilda, for example, are too similar, since they both start with the letter ‘M’, both end in ‘a’ and are similar in length.

I’m told that a reader could easily confuse Erika and Heiki because of the ‘ik’ in the middle, I suppose, even though they start with different letters.

Mary Louisa Locke has an interesting and helpful article on the subject here.  

Scrivener includes a writers’ tool to generate names. The tool allows selection of the ethnic origin of the first and second names. This is very helpful, and I use it a lot.

The first draft of my detective thriller, St Patrick’s Day Special, contained lots of Irish names which I thought were sufficiently dissimilar, but my editor pointed out that too many of them ended in the letter ‘n’. Names like Finnegan, Gilligan, Flanagan, even Allen would confuse the reader, especially as my main character was called DI Ben Jordan. It’s quiet amazing how many Irish names end in the letter ‘n’, and if you count the number of Irish names that include that letter anywhere (like Toner, Byrne, Norris etc.) you get a huge list. A smaller list, but equally confusing for the reader, is the list of names ending in ‘y’: O’Flaherty, Flatley, Cudihy, O’Malley, and so on.  English names ending in ‘r’ must be legion. Think of Miller, Baker, Archer, Fletcher, and so on.

 I took a quick look through the Dublin telephone book for names ending in ‘n’. These I picked out from the ‘Bs’

Bacon, Baldwin, Banahan, Bannon, Bannigan, Behan, Belton, Bohan, Bowden, Boylan, Bracken, Branagan, Brannigan, Breen, Brennan, Breslin, Brown, Bruen, Buchanan

Of course lots of Irish names start with O’ like O’Reilly, O’Higgins, O’Bama and so on, and many start with Mac or Mc.

While writing my WW2 novels, The Black Orchestra and its sequel it was important to be able to distinguish German names from the 1940s that would have been recognizably Jewish. This is a tricky area. Google provided a selection of web sites that were helpful; none that I could recommend, though.

In early drafts, while choosing (both first and second) names for characters, I like to keep them uniquely identifiable, so that I can use the Search/Replace_All function to change them at a stroke if I need to. An example: Suppose your working name for a character is Sam Small. If, prior to publication, you decide to change this name to John Carpenter, and use Find/Replace_All to change all occurrences of Sam to John, and Small to Carpenter. Your word processor will transform words like ‘sample’ into ‘johnple’ and ‘same’ to ‘johne’. Obviously, changing ‘Small’ to ‘Carpenter’ everywhere is going to produce a lot of unwanted changes to the text, too.

The simple way out of these problems is to call your character Sam* Small* right from day 1. The asterisks make the names unique and Find/Replace_All will work like a charm. If you use the asterisk for nothing else, then their final removal is a simple matter.

It’s at times like these that I wish I had a small spark of the genius of Charles Dickens. His character names are so inventive, and many have entered the English Language. Here’s a few of them, mainly from this web site

Skimpole, Sloppy, Ebenezer Scrooge, Bumble, Sweedlepipe, Pumblechook, Pickwick, Wopsle, Polly Toodle, Wackford Squeers, Honeythunder, Tulkinghorn, Lady Dedlock, Captain Hawden, Oliver Twist, Silas Wegg, Boffin, Dick Swiveller, Smike, Uriah Heep, Wickfield, Sowerberry, Podsnap, Lucretia Tox, Sophia Wackles, and, of course, Bullseye the dog.

One more tip: If you are planning to seek representation from a literary agent, avoid names that end in ‘ly’. The agents have a fatwa on adverbs, and I suspect that they search submissions looking for words containing ‘ly’. My second thriller is called Find Emily. It contains 768 words ending in ‘ly’, but 227 of these are ‘Emily’.

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Writers – Writing Tip #10

This is the tenth of 12 posts for writers who are planning to self-publish using the great services now available to the amateur writer, such as Smashwords, Amazon KDP, CreateSpace etc.

These mistakes are straight from week1 of “Good Writing 101”. You might get away with one or two of them; maybe people won’t notice. But if you consistently break these rules better not give up your day job.

10. Don’t Screw Up the Ending

I probably spend more time working on the last 5% of each book than I spend writing the rest of it. That’s because the ending needs to be perfect, and endings are tricky.

First, the ending has to be logical. If there’s a mystery to be solved, the solution must make sense and it must be something that the reader could have worked out for herself. There’s nothing worse than a whodunnit where the guilty party is someone that appears for the first time on page 352. Nearly as bad is where the guilty party was introduced on page 10 and hardly ever (or never) mentioned again until the end of the book.

You need to get the pace of the ending right. Many endings read as if the writer lost patience with the book or thought of something urgent that needed doing in the kitchen. If you rush it, the reader will hate you; if you drag it out she will lose her patience with you. The pacing needs to be just right, like Goldilocks.

Consider the taste that the book leaves in the reader’s mouth. Is it bittersweet or will you leave the reader punching the air in shared triumph or cheering or laughing or crying? All of these are possible choices. It really depends on the rest of the book. But make sure it’s consistent with the tone of the book.

The ending needs to tie up loose ends. First, you have to know what the loose ends are. Make a list. Leave it sit for a week, and then revisit it. Are they all there? Consider your minor characters: do they have issues, hopes, ambitions that need to be resolved? Once you have a full list, think about each one. Normally, you should aim to resolve them all, but consider whether it might be better for the story if one or two are left hanging. Sometimes it’s better to let the reader decide, in her own mind, one or two ending outcomes. There are many great books that leave the reader guessing. The Road by Cormac McCarthy comes to mind. If you are planning a sequel, you may need to leave something unresolved, of course. If in doubt, give the manuscript to as many beta readers as you can. Keep the last few pages back, and ask them how they think the book will end. Chances are you’ll get a wide range of responses, and some will surprise you and make you rethink your ending.

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Writers – Writing Tip #9

This is the ninth of 12 posts for writers who are planning to self-publish using the great services now available to the amateur writer, such as Smashwords, Amazon KDP, CreateSpace etc.

These mistakes are straight from week1 of “Good Writing 101”. You might get away with one or two of them; maybe people won’t notice. But if you consistently break these rules better not give up your day job.

9. The Big Explanation at the End

Remember all those Agatha Christie mysteries where Hercule Poirot gathered all the suspects together and ran through the clues that led him to the final unmasking of the guilty party? Well the world of fiction has moved on. My editor tells me that nowadays all explanations must be revealed within the action.


“But what I don’t understand, Gray Cloud, is how the medicine man knew where to find the Vince Lombardi trophy.”

Gray Cloud sat by the fire and crossed his legs. “We must assume that Billy-Bob Wilder gave him the information. Remember when the two of them were incarcerated together for a week by Lucy, the preacher’s mad daughter? Rutting Bison shared his pipe with Billy-Bob. It seems the pipe was primed with hallucinogens that loosened Billy-Bob’s tongue.”

“Rutting Bison must have known that the drugs were hidden inside,” I mused.

“I don’t think so,” said Gray Cloud, shaking out his dream catcher. “The medicine man had nothing but disdain for modern drugs, and no interest in money. I think you’ll find all his actions were driven by the purest of motives.”

“Including the murders?” I threw him a look of total incredulity.

“You’ll understand when you’re older, son,” he said. “It’s a Native American thing.”


“Come out with your hands up,” I shouted. “And bring the trophy with you.”

The medicine man appeared at the entrance to the hogan, and threw the precious Vince Lombardi trophy in a hail Mary pass high over Gray Cloud’s head. I ran and caught it before it hit the rocks.

As Gray Cloud handcuffed him I asked the medicine man, “Who told you where the trophy was hidden?”

“That fool, Billy-Bob Wilder was happy to tell me after sharing my happy pipe,” said Rutting Bison with a scowl. “The paleface nearly lost his mind when Lucy, the preacher’s mad daughter, locked the two of us up for a week with no food or water.”

“Of course your spirit creature protected you,” muttered Gray Cloud. “But tell the kid how you knew the drugs were inside the trophy.”

“Drugs?” the medicine man snorted. “If you think that was what I was after you are even more foolish than I thought, Gray Cloud. Everything I did I did for the tribe.”

“Including the murders?” I said, incredulous.

“You’re too young to understand,” said Gray Cloud. “It’s a Native American thing.”

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Writers – Writing Tip #8

This is the eighth of 12 posts for writers who are planning to self-publish using the great services now available to the amateur writer, such as Smashwords, Amazon KDP, CreateSpace etc.

These mistakes are straight from week1 of “Good Writing 101”. You might get away with one or two of them, but if you consistently break these rules  readers will notice.

8. Repetition

Try not to repeat yourself. This is the sort of mistake that should be picked up easily by an editor, or even a proofreader. Here’s an example.

Inspector Bill Marsden scrutinized the murder scene. The bishop’s body had been removed, a chalk mark indicating where it had lain on the carpet. Otherwise, the crime scene was undisturbed. The blue carpet was stained brown with a pool of dried blood. The poker, also streaked with blood, lay on the hearth where the murderer had dropped it. The forensic team would dust that for fingerprints, although Marsden knew they would find none. Whoever had killed the bishop had been careful to leave as few clues as possible.

He checked all the doors and windows. None had been forced. It seemed the bishop was acquainted with his murderer.

His phone rang. It was Marsden’s nemesis, Chief Superintendent Lamb. “What have you got, Inspector?”

“I’ve gone over the scene again,” said Marsden. “My guess is that his eminence knew his killer — there’s no sign of forced entry.”

“Tell me you have something to go on, Bill,” said the chief.

“There’s a lot of blood, sir, and we have the murder weapon. It’s a poker, but I’m afraid forensics won’t find any prints on it. Whoever the killer was, he was careful not to leave any clues.”


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Writers – Writing Tip #7

This is the seventh of 12 posts for Writers who are planning to self-publish using the great services now available to the amateur writer, such as Smashwords, Amazon KDP, CreateSpace etc.

These mistakes are straight from week1 of “Good Writing 101”. You might get away with one or two of them; maybe people won’t notice. But if you  consistently break these rules don’t give up your day job.

 7. Exposition

Exposition, my dictionary says, is “a comprehensive description and explanation of an idea or theory.” For fiction, that includes background, world building and backstory.

Let’s suppose you are writing a science fiction story about an alien invasion of the Earth. In order to tell the story properly, the reader will need to know why the aliens had to leave their own planet, the reason why they chose our planet to invade, and what steps they have already taken (before the story starts) to terraform the Earth to suit their biological needs. The reader will also need some details about how the Earth is now governed by a single power, Earth-gov, headed by an Earth President called Michaels.

All of this information must emerge in the most natural way possible, without interfering with the flow of the story. The golden rule here is to provide just enough information at each point so that the reader can follow the story, and no more than that.

Any attempt to interrupt the story in order to describe or explain this sort of material to the reader, will come across as authorial lecturing, and you run the risk of boring the pants off your reader.

The worst method of all is ‘feather dusting’, where two characters discuss something simply in order to impart information to the (eavesdropping) reader.

“As you know, Bob, the aliens lost control of the climate on their own planet hundreds of years ago, and set out in their inter-galactic spacecraft to find a new home.”

“But what I want to know, Bill, is why they chose Earth.”

“I think it was our water that attracted them, Bob. That and the ease with which they could terraform the planet to suit their biological needs.”

“I read somewhere that they prefer an atmosphere with more nitrogen in it. I suppose that’s why I feel so lightheaded all the time.”

“You’re right, Bob. Hopefully President Michaels and his Earth-gov will do something about it soon.”

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