What Is a Lexile Measure?

The Lexile® Framework for Reading is a reading metric that matches readers with text targeted to their ability level. Readers and text are measured on the same developmental scale. Developed by MetaMetrics®, Inc. this scientifically-based approach allows users to easily identify text at a difficulty level that will be appropriately challenging to improve reading skills.

How Is a Lexile Measure Represented?

A 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.

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). All the passages in Total Reader's library have been analyzed using the Lexile Analyzer. The Analyzer splits text into 80-word slices. Each slice is compared with 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 familiar words appear frequently in these books. Conversely, books in the Harry Potter series (880L - 950L), Little Women (1300L), and Don Quixote (1410L), contain longer sentences and more complex, less common words.

How Is a Reader’s Lexile Measure Determined?

Students select and read age-appropriate Lexiled passages, each with a series of omitted words, called cloze items. For each omitted word (which is representative of the text's overall Lexile measure), the student sees four possible substitutions; by clicking a word, the student fills in the text and can continue reading. The cloze item is presented within the context and flow of the reading passage; the student need not stop or move back and forth between a separate answer page and the passage. The content and associated cloze items are referred to as passages.

After a student completes an initial set of passages (the equivalent of 45 cloze items), Total Reader produces a Lexile measure. All subsequent passages completed will monitor the student's Lexile measure and report the new measure when change occurs. This way, Total Reader continually generates updated Lexile measures and students are always aware of their reading range. Students have access only to passages in a range from 100L below to 100L above their current measure. This is consistent with The Lexile Framework guidelines for independent reading. The system records progress and represents it in a series of reports.

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