Why do a book’s Lexile level and GRL not agree on grade level?
The reason for differences between Lexile levels and GRLs is that they measure slightly different things. A Lexile is a unit for measuring text difficulty, focusing on the two variables of semantic difficulty and syntax. GRLs take other factors into consideration, such as complexity of story structure, spacing, and conceptual elements. If a book has advanced vocabulary but little text and story structure, it may have a very high Lexile and a low GRL.
