The Lexile® Framework for Reading was created by MetaMetrics® to measure the reading challenge presented by a text. In contrast to a district's age-based guidelines for what students should read, a Lexile measure is quantitative. Measures range from below 200L to above 1700L, and are based on both reading ability and text difficulty.
The Lexile® Framework for Reading is a scientific approach to reading and text measurement. There are two Lexile measures: the Lexile reader measure and the Lexile text measure. A Lexile reader measure represents a person’s reading ability on the Lexile scale. A Lexile text measure represents a text’s difficulty level on the Lexile scale. When used together, they can help a reader choose a book or other reading material that is at an appropriate difficulty level. The Lexile reader measure can also be used to monitor a reader’s growth in reading ability over time.
It is important to note that the Lexile measure of a book refers only to its text difficulty. A Lexile measure does not address the content or quality of the book. A Lexile measure is based on two strong predictors of how difficult a text is to comprehend: word frequency and sentence length. Many other factors affect the relationship between a reader and a book, including its content, the age and interests of the reader, and the design of the actual book. The Lexile measure is a good starting point in the book-selection process, but these other factors should be considered when making a decision about which book to choose.