What is the Lexile Framework?

The Lexile Framework is a tool for looking at a reader’s ability in relation to the difficulty of specific texts. For example, given three books - The Cat in the Hat, Charlotte’s Web, and Ivanhoe - you would easily be able to sequence them in terms of difficulty. However, given Harriet the Spy, Little House on the Prairie, and The Boy Scout Manual, you may find the task a bit more daunting and time-consuming. The Lexile Framework handles this for you.

By the same token, readers can also be ordered by ability to read, and there are many methods, formal and informal, for accomplishing this. But, until now, there has never been a way to put the two together, measuring readers and text using the same scale. The Lexile Framework provides a single scale that can be used for targeting readers with text that provides an appropriate challenge.

The work that led to development of the Lexile Framework was based on forty years of research on how students acquire reading skills. It was funded in part by federal government grants through the National Institute for Child Health Development (NICHD). The grants supported research on not only reading, but also psychometric theory that would enable placing students and text on a common scale. MetaMetrics analyzed the work of Chall, Flesch, Carroll, Bormuth, and Klare concerning readability and George Rasch on measurement. Contributors included Dr. Benjamin Wright of the University of Chicago, Dr. Donald Burdick of Duke University and Dr. John B. Carroll, Professor Emeritus, University of North Carolina.

The Lexile Framework measures the difficulty of text using transformations of sentence length and frequency of word usage. These two counts are used to operationalize the syntactic and semantic variables in a theory of reading development. As readers become more proficient, they gain facility with increasingly complex syntax and gain sight recognition of increasingly rarer words. Thus, text and readers are conjointly ordered relative to the same two variables.

The raw score performances of readers are converted into Lexile measures via a theory of what makes text more or less challenging to the reader. Forecasted comprehension is a function of the difference between the reader measure and the text measure. When readers are well targeted (difference between text and reader near 0L) comprehension is modeled to be 75%. When a text measure exceeds a reader measure by 250L the modeled comprehension drops to 50%. When a reader measure exceeds a text measure by 250L the modeled comprehension goes up to 90%.

The Lexile Framework affords the teacher and parent a useful tool for programming success into the reader's experience. When readers read well targeted texts, they report confidence, competence, and control of the text. When teachers listen to readers read targeted text aloud, teachers report the reader is comprehending what he/she is reading. Thus, the objective report of a correspondence between the data, the subjective report of targeted and is targeted readers, and teacher ratings support the conclusion that the Lexile Framework is describing an important dimension shared by readers and texts.