"The Lexile Framework for Reading is a scientific approach to measuring reading ability and the text demand of reading materials. The Lexile Framework involves a scale for measuring both reading ability of an individual and the text complexity of materials he or she encounters. Tens of millions of students worldwide receive Lexile measures to help them choose targeted readings from more than 100 million articles, books and websites that have been measured" ("Lexile Measures").
Reading research suggests that children grow the most as readers when they read books that are just right for them. When a book is neither too easy nor too hard, students can practice their reading and comprehension skills best and show the most growth. Lexile ranges help students choose books that are "just right" for them.
However, it's important to remember that students should also be encouraged to choose books that fall outside of their Lexile range. This means that students should be encouraged to read books that are too easy, too challenging, and just right - just as an adult would. Studies show that children who are free to choose the books they want to read, regardless of the book's level or content, are more likely to read for pleasure and read for life.
For more information please see the following sources of information:
Krashen, Stephen D. The Power of Reading: Insights from the Research. Libraries Unlimited, 2004.
“Reading for Pleasure - a Door to Success.” National Library of New Zealand, natlib.govt.nz/schools/reading-engagement/understanding-reading-engagement/reading-for-pleasure-a-door-to-success.
“Lexile Measures Now Better Match Beginning Readers to Text.” MetaMetrics, MetaMetrics Inc., 19 Sept. 2017, metametricsinc.com/about-us/news/lexile-measures-now-better-match-beginning-readers-text/.
MetaMetrics develops scientiﬁc measures of academic achievement and complementary technologies that link assessment results with instruction. Our products and services help learners achieve their goals by providing unique insights about their ability level and potential for growth.
Stephen Krashen is an influential American educational researcher from the University of Southern California. His work centers on second language acquisition and the power of free voluntary reading.