The debut novel of internet star Zoe Sugg is more popular among secondary school children than books by well-known names such as Jeff Kinney and Cassandra Clare, it has been suggested.
Girl Online by vlogger Sugg - who is also known as Zoella - was the top pick for those in secondary school, as well as a favourite among primary school children, according to research by online education company Renaissance Learning.
The study is based on an analysis of software that assesses the books children read and their understanding of those stories. Youngsters take comprehension quizzes on the fiction and non-fiction books that they read, with more than 12.5 million taken between August 2014 and July last year.
It looked at two categories: "most read" - the number of times a title was read in school - and "most popular" - the books that children say they enjoy reading the most, and found differences between the two.
Sugg's novel was the most popular book among secondary school children, followed by The Maze Runner by James Dashner. Three of Rick Riordan's House of Olympus series made the top 10, along with three novels by Clare. Also making it into the top 10 were The Dying Of The Light by Derek Landy and Christopher Paolini's Inheritance.
In comparison, Kinney's Diary Of A Wimpy Kid: The Long Haul was the most read book in secondary schools. It was also the most popular novel among primary school pupils.
Overall, seven books in the Wimpy Kid series were among the 10 most read books for secondary-age children, along with Gangsta Granny by David Walliams, The Hunger Games by Suzanne Collins, and Roald Dahl classic Charlie And The Chocolate Factory.
Girl Online was the seventh most popular book among primary school children - a list that also included five of JK Rowling's Harry Potter books, two of Collins's Hunger Games series and Opal Plumstead by Jacqueline Wilson.
The most read book for this age group was The Twits by Dahl, who was one of just three authors to feature in this top 10, alongside Kinney and Walliams.
The study found boys continue to prefer non-fiction works, and that at primary level they tend to focus more on one author, whereas girls prefer more variety.
It also noted that during primary school, pupils tend to read favourite books that are above the difficultly level for their age group, but this stops once their go to secondary school.
"At this point favoured books are no longer a year above chronological age, but a year below it, and in ensuing years the difficulty of books plateaus or declines," the report says.
Report author Professor Keith Topping said: "This year's findings reveal that, strikingly, children read their favourite books at a much higher level of difficulty and with a greater level of comprehension than those recommended to them.
"Clearly, this suggests a way of responding to the problem of insufficient challenge which is particularly prevalent in the secondary years. Instead of recommending books to children, teachers, librarians and parents should be finding ways to enable children to recommend books to each other."