Completion Rate

A book’s completion rate is a measure of how strongly readers engaged with the book’s content. Did the narrative glue readers to the book from start to finish and did it keep them coming back after they paused to pursue other activities?

In calculating a book completion’s rate, we look only at users who send us reading data. We do not included readers who download the book, but did not proceed to read the book. There are many reasons why this may happen. The most common reason is an initial intention to read the book, but work, family or life in general then get in the way. Books have high optionality after all, they keep waiting for us.

We send participants who download a book, but do not start reading the ebook, two nudge emails to ensure that they don’t simply forget about the ebook sitting on their phone, tablet or other device.

The completion rate is calculated by taking the number of readers who reached the final chapters of a book and divided by the number of total readers who sent us reading data at any point in the book. Usually the peak is in chapters 1, but it is not unusual to see the peak reader number in the front matter (cast of characters, introduction or overview) prior to the readers even reaching the first chapter of the actual storyline. This is often the first sign that reader engagement for the book is not going to be strong. A book with a high completion rate usually has its peak in chapter 1, declines gradually in the first couple of chapters and them has steady reader engagement for the remainder of the book.

Completion rates do not appear to be genre dependent. They can vary from zero to one hundred percent in almost every genre and area we have looked at.

A result below 25% usually indicates weak engagement and is accordingly colour coded in a light blue.

A result between 25 and 50% is a good result and is achieved by the majority of books. It represents OK engagement between the book and reader, but does not signal breakout potential. We colour code such results in light yellow.

A result over 50% is very good, especially for non-fiction and indicates a book that stands above the rest and is colour coded green accordingly.

A completion rate over 75% is exceptional and colour coded purple. Fewer than 5% of book Jellybooks has tested reach this level and they include some the biggest bestseller of recent years. There is a high correlation between a book exceeding 75% and performing very well in the market. The closer a book gets to this mark, the stronger it is.