A Lexile measure is a standard used to evaluate the reading ability of individuals and the difficulty of texts. It provides a numerical score that indicates the complexity of a text, helping educators match students with appropriate reading materials. The measure ranges from below 0L for beginning readers to above 2000L for advanced texts. Lexile measures are determined through assessments that analyze factors like vocabulary and sentence length. This system allows teachers and parents to track reading progress and select books that align with a student's reading level, promoting effective learning and comprehension skills.