Lansing value is a grading standard formulated by the National Center for Child Health and Development, which is used to measure readers' reading level and the difficulty of identifying publications. Simply put, a Lexile is a unit of difficulty, and the gap between reading a primary book and reading an encyclopedia is defined as 1 Lexile. Lance's highest score is1700 l. For example, the lexile value of Harry Potter series is about 800 to 1000, while the magictreehouse and myweirdschool series of elementary chapter books are about 600. Each book can go to lexile website to check the corresponding lance value, or you can submit the book to test it yourself.