Here’s a big question: why do most successful self-publishing authors write series rather than standalone books? The answer is quite simple: once you manage to hook a reader into a series, they are likely to buy all the books in that series.
Let’s say you’re able to sell a standalone book to 1,000 readers. But what if that book is not just a standalone, but the first in a series of five, and those 1,000 readers read all of them?
In the end, it’s just as hard to sell a standalone as it is to sell book one of a series. It’ll take the same kind of marketing effort (e.g. the same advertising money). But in the case of the series, the potential returns are much, much greater.
What does a series mean?
When we talk about a book series, we normally think of novels right? Jack Reacher, Harry Potter, Poirot, or the epic fantasy series of writers like George R.R. Martin and Robin Hobb. But series aren’t limited to fiction. Plenty of nonfiction authors have successfully created a series—which is pretty straightforward in some cases.
For example, Joseph Alexander is a musician who first published a jazz guitar tutorial book which sold pretty well. He then put another book out focusing on blues guitar, and then another one offering more lessons in other styles. And then before he knew it, he had published dozens of guitar books that now earn him over $800,000 a year in royalties.
A basic principle of series publishing is that you only really need to advertise the first book. As soon as the reader is finished, they can see in the back pages that there are follow-ups (and a way for them to join your mailing list, where you can then contact them every time a new entry in your series comes out).
As you may have already figured, not everyone who reads book one will move onto book two. And not everyone who gets to your third book will necessarily buy book four. That’s why it’s important to know your series’ read-through.
Read-through (RT) is basically the percentage of readers of a book in your series who go on and read the next book.
For example, if 100 people read your first book and 75 of them go on to buy and read your second one, your read-through from book one to book two is 75%. Then, if 60 out of these 75 end up reading book three:
● RT from book two to book three = 60/75 = 80%
● RT from book one to book three = 60/100 = 60%
What does read-through actually mean?
In essence, read-through is a good scientific measure of how “unputdownable” your series is. If 80% of the readers who buy the first book go on to read your entire series, then you've created a series that turns four out of five casual readers into hardcore fans.
On the other hand, if only 25% of readers who buy book one ended up buying book two, then you know you have a problem with book one, or how you’re marketing it. Maybe your story (or your arguments, for nonfiction) aren’t compelling enough and readers don’t even finish the book. Perhaps you’re targeting the wrong people, or your book cover gives the wrong impression. Or maybe book two is simply priced too high.
You should regularly monitor read-through across your whole series as that will tell you where you start losing the most readers.
For example, if RT from book one to book four is 60%, but only 25% from book one to book five, then you know you’re losing a ton of readers at book four! Again, there can be hundreds of reasons for that, and RT alone won’t tell you which one it is. But at least you’ll know there’s a problem.
What does read-through mean for advertising?
Let’s say that you’ve published this great series and are just starting to play with Amazon ads. You’re advertising the first book, which you’ve priced at an entry level of $0.99. You’re getting lots of sales at an average advertising cost of 50%, which means that every 99c sale you make from these campaigns only costs you 50c.
This sounds great, but the problem is that your royalty on that book might be only 35%. So every sale earns you 35c — not 99c — and costs you 50c.
Naturally, you think “I’m losing money here!” and kill the campaign.
What have you missed? The read-through, of course! You've paid to get readers to buy the first book but a percentage of those readers will naturally go on to buy book two. Stop to do that math, and you may have just killed a campaign that's making three times what you were spending.
If your aim as an indie author is to become financially viable, you need to play the long game. By understanding the lifetime value of your readers, you’ll start to get a picture of why it’s so important to consider the series potential of any book you’re writing. As your books keep enthralling your fans, you can keep benefitting from the investment you made in advertising your first book.