Book series: what you can learn by examining the sales curves

Does the launch of a new book in a series stimulate the sale of previous ones? Apparently, this is the case. At first, this was a gut feeling, so I decided to plot some sales graphs and see it for myself. I would like to direct your attention to a few interesting observations which came apparent by examining this data. Note that I purposefully hid the x-axis (number of copies) and the years on the y-axis to preserve the anonymity of the concerned publishers. Each line represents the sales of an individual book in the series.



These two first graphs are typical examples of a “normal” situation. The books are launched at regular time intervals and almost every time the launch stimulates the sales of the older books. The new books perform better than previous installments for a few of months, then join the overall trends and sales volume as the preceding one.


Here we can observe an atypical phenomenon: the launch sales of volume 3 (in blue) were lower than the sales of the first volume of the series (in purple) during one month. I double checked the data to make sure a price drop on volume 1 could not be held accountable for this situation. Perhaps the launch of volume 3 aroused reader interest in previous installments of the series, which led to an increase in sales of volumes 1 and 2, instead of energizing sales for volume 3. This publisher should take a look at marketing actions he had taken for the launch of the previous volumes to see why the first two volumes did not appear to have as big an impact following their own launches.


The graph above shows typical curves, but we see that a promotional action in December gave a boost to sales, thus extending the sales period of volume 2 and preventing it to decline rapidly following its launch.


This is a case of an older book series. Originally available in PDF format only, the series was converted to EPUB in March and re-launched, with a special promotional effort on volume 1. This book was very successful, thus driving the sales of the other volumes.

By examining these graphs, we can see that, when launching a new book in a series, it is of utmost importance for your marketing campaign to consider these two elements:
– Remind readers of the existence of the entire series
– Ensure easy access to previous books in the series

You should spend a few minutes to look at your own book series sales statistics. They can serve as a diagnostic tool to spot potential problems and measure the results of your commercial actions.

Leave a comment