Lexile Information

  • The Lexile Framework® for Reading is a scientific approach to reading and text measurement. It includes the Lexile® measure and the Lexile scale. The Lexile measure is a reading ability or text difficulty score followed by an “L” (e.g., “850L”). The Lexile scale is a developmental scale for reading ranging from 200L for beginning readers to above 1700L for advanced text.

    Lexiles are reported as a range of scores (150 point range). The upper part of the range (top 50 points) might be used for the student’s group reading program (he/she will need some assistance with the vocabulary). The lower part of the range (lower 100 points) might be used as a target for the student’s independent reading (reading a book for pleasure with little or no assistance). The top 100 is where the student comprehends about 75% of the material. For example, if a student's Lexile range was 500-650L then if he/she was reading a book within the range of 600-650L, he/she would need some assistance. If the student was reading a book within the range of 500-600L, then he/she would be able to read it with little or no assistance.

    To access the Lexile website visit www.lexile.com.


    How is a text's Lexile measure determined?

    Lexile measures are based on two well-established predictors of how difficult a text is to comprehend: semantic difficulty (word frequency) and syntactic complexity (sentence length). In order to Lexile a book or article, the text is split into 125-word slices. Each slice is compared to the nearly 600-million word Lexile corpus – taken from a variety of sources and genres – and words in each sentence are counted. These calculations are put into the Lexile equation. Then, each slice’s resulting Lexile measure is applied to the Rasch psychometric model to determine the Lexile measure for the entire text.

    For example, books like "Arthur and the Recess Rookie" (370L), "Arthur Goes to Camp" (380L) and "Arthur, Clean Your Room!" (370L) fall within the Lexile Range of a typical second grader. These books have shorter sentences and words that appear frequently. Conversely, books in the "Harry Potter" series (which measure between 880L and 950L), "Little Women" (1300L) and "Don Quixote" (1410L) contain longer sentences and more complex words.

    What is the Lexile Book Database and what can I do with it?

    Once you have a student's Lexile measure, you can search the Lexile Book Database to find books that are similar to the student's reading level. This database contains tens of thousands of fiction and nonfiction titles with Lexile measures. You can search by title or author, Lexile range or keywords, or ISBN. The Advanced Search feature allows you to search by the same basic parameters, plus Lexile codes, publisher, copyright year, doctype (fiction or nonfiction), reading series, book awards, and developmental rating.