While Lexile levels are widely used in schools and libraries as a tool for selecting books for children and adolescent readers, they are frequently overused and misused. Lexile scores determine "readability" (a numeric ratio of sentence length and syllables per passage); they cannot account for content complexity or student interest in the subject matter. Teachers of reading, literacy coaches, parents, and librarians should not rely on Lexiles to choose books for children. Lexile levels should be but one measure for determining a book's appropriateness for a given reader. Reader interest should be the top consideration! A wealth of research (as well as anecdotal evidence) shows that truly engaged readers can and will read texts above their Lexile level and above their "zone of proximal development" (Vygotsky).

The information below describes why a reliance on Lexiles is very problematic.