How does Sparx Reader determine the reading ages of the books?

Book reading ages 

Sparx Reader has books suitable for a vast range of reading ages, from a reading age of approximately 5 up to a reading age of 16 and beyond. There are many books available on Sparx Reader at each reading age, covering a range of genres and themes. 

Amongst our titles for students with a reading age of 5 or 6, we have several ‘High-Interest Age, Low Reading Ability (Hi-Lo)’ titles from Badger Learning, which have been designed for reluctant readers at secondary school.

For the very strongest readers, we have a range of engaging and challenging titles, including some classic titles and many modern day texts. 

You can see the full range of available books, as well as information about each one, on the Sparx Reader Library page. 

Determining the reading age of a book

When books are first released onto Sparx Reader, the reading age is set by our internal experts, who use their many years of teaching experience and content creation experience to estimate the difficulty of the books. Many factors are considered by the team such as:

• The vocabulary used

• The sentence length and text structure used 

• The themes presented in the book

• The amount of prior knowledge needed to understand the book

• The pace of the book

• Guidance from the publisher

• The reading ages of similar books

Once students start to read the books on Sparx Reader, we further refine the reading age assigned to a book using this real-world data. The reading ages for books are refined by measuring how well students are reading them (how quickly and accurately, based on the end-of-section quizzes), taking into account the ability of the students. 

With over a hundred million question attempts, we’re able to build a strong picture of the relative difficulty of each book. And because we know each student’s age, we can estimate the ‘real-world difficulty’ of the book: if a book is achievable by thousands of 14-year-olds, then it really does have a reading age of 14.

Example: When the Sky Falls by Phil Earle

When the Sky Falls is an award-winning title by author Phil Earle which can be found in bookshops and libraries all across the UK. It is an emotional story that follows Joseph as he relocates to a London zoo during The Blitz in 1941. When we acquired this book for Sparx Reader, we thought about how students would be best placed to succeed in reading World War II texts. We considered the 10-11 reading age suggested by the publisher, Andersen Press, and booksellers. We also factored in school curricula which include World War II in Key Stages 3 and 4. We further considered the cultural capital and vocabulary gained by learning about British history in school and we then designed question content appropriate for the book based on this. Finally, we thought about the reading age at which students could complete When the Sky Falls through independent reading. As a result, Sparx opted for an initial reading age of 13. Over time, the Sparx Reader model has increased the reading age to 14, reflective of student reading activity, aligning with Key Stages 3 and 4 curricula of World War II teaching.