Michael Zwaagstra: Reading comprehension depends on content knowledge

Walk into an elementary-school classroom and you’ll probably see a lot of books on the shelf. Take a closer look and you’ll often find a coloured dot, a number or a letter on each book’s spine. Those dots, numbers and letters show the reading level of each book.
Books are assigned levels so students choose books that will challenge them without being too difficult. Instead of having the entire class read the same book, students pick books from their designated reading levels. L