Let’s talk about writing in series and standalones. Now, we’ve talked repeatedly about how writing in series makes it much easier to market your work. While I don’t have any definitive numbers (not sure anyone does); but my experience has been that you get:

  • True Fans – 1 in 600 (i.e. for every 600 readers you generate, you get 1 true fan who’ll buy everything you have, no matter what genre of book or series you write in).
  • Genre Fans – 1 in 67 (that is, they’ll follow you from one series to another)
  • Series Fans – whatever your readthrough is, in my case for my bestselling series, that was 1 in 5. You should have, from the previous chapter on readthrough rates, done the math on your own series.

Now, all this is based off me looking at my own bestselling series, taking total number of fans and converting them to my other series. In some cases, that’s cross-genre works, other cases in-genre works. These numbers will different and probably have a lot of variability for others; however this does offer some thoughts.

However, what I wanted to talk about, more than anything else, is the optimal number of books in a series.

Readthrough Rates and Falling Readers

Let’s take one of my bestselling series, the System Apocalypse. Book 1 to 2 Read-through was 77% or 84% (sales or KU reads). That was my lowest readthrough, with 6 books (out of 12 books in the series) having readthrough rates over 90% and the rest 80%+.

Those are incredible readthrough rates.

After 12 books, do you know what my readthrough rate from someone picking up book 1 and finishing the series? 28% or 22% (sales or KU). So, in total, roughly 1 in 4 readers managed to finish this series.

And that’s with a hit series.  Take the same math, and do it with same an ‘average’ series and you can see the chart below.

Now, this is a very simple chart, assuming you get similar readthrough rates all the way across. This isn’t actually normal, what you get is more like this, where the first book 1 to 2 drop is much higher (in the 50-70% range). Then, you often stabilize if the book is ‘good’ at a higher level, like 70-80% readthrough rates.

So you get a chart closer to this (I changed the 50-70% numbers, left the 80% and onwards numbers).

Of course, these aren’t ‘real’ numbers, individual books and arcs will change readthrough rates, prices and promotions and formats (see above my note about my own KU and sales numbers for System Apocalypse) will effect things.

The main point? Do your math by the time book 2 comes out. You NEED to know when to stop and plan for that.

Planning for Failure

One of the smartest things I ever read was from Patty Jansen. She mentioned planning to end a series when you have 1 book, 3 books, 5 books, 6 books and 9 books in. I can’t recall if she mentioned not going past 9 books, but if you look at the numbers, unless you’ve got a really, really hot series with excellent readthrough rates, it becomes much, much harder to sustain writing long works.

As you can tell, the biggest and most important drop is book 1 to 2. If you have a very large drop-off from those books, it’s worth relooking if you can continue the book even if you get good readthrough after that. I won’t get prescriptive of when you should cut a series short (if you had a plan for a longer work); but 3-6 books for most series seem to be the right place to end I would say.

Mind you, what I’m discussing are straight-line series which have only a single entry point. There’s a reason why tradpub did trilogies that were all part of the same story, but had multiple entry points. Or why work like Terry Pratchett’s Discworld series which, again, had multiple entry points into the world; continued for so long.

Further Complications

The first, about increasing number of readers in-between books has been discussed. That’s something that is always worth noting, that in-between releases, you do get additional readers who come in, such that each successive book launch might be larger than the previous one especially if your drop-off is low. This can often mean escalating revenue too; though you have to be careful since without an end in sight, readers can grow tired of the series fast.

This increase in readers often happens with hit series, with works that have become ‘evergreen’ and gained significant mass appeal and thus are mentioned in social media posts, reviews, word of mouth, etc. often. In these cases, while your readthrough rate (which is a %) might not change much; the numbers filling in at the top can have vast impact.

Secondly, omnibuses and other collections change these numbers a little. My readthrough rates for the omnibus editions are actually quite different than for the full series. By bundling book 1 to 2 together, you can find that readthrough for book 4 (because most bundles are 1-3) is much higher than previous.

Readthrough on other formats are another aspect. Audiobook readthrough can be different than for ebook or print readthrough, which is something you have to consider.

End of the day, do the math for each of your individual series to work out what is best for you. Don’t rely on assumptions, use the excel sheets to work out what the optimal scenario for you to stop writing might be.

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