Primary and Secondary Textbook Complexity in England

The study examined the text complexity of textbooks available for use in English maintained primary and secondary schools that address select mandatory courses: English, mathematics, science, history, geography, and citizenship, for years one through 11, key stages 1 through 4.
The research hypothesis was that text complexity varies within school year and key stage and that the median text complexity increases with school year/key stage. The results supported the hypothesis. However the findings highlight the fact that the greatest increase in complexity across the years and key stages occurs early on when young readers are still developing their reading skills: between years one and two and between key stage 1 and 2. After this time, the increase in complexity is less marked.