What is the difference between the recommended Lexile range and Renaissance Learning’s ZPD range?
Both the Lexile range and Renaissance Learning’s Zone of Proximal Development (ZPD) range are based on the premise that students can optimize their reading growth if they read books at a level that is appropriately challenging. The books should be challenging enough so that new learning occurs (e.g., the student encounters some new vocabulary), but not too difficult that students get frustrated and give up. However, the actual recommended reading ranges for the two systems are quite different. A student’s Lexile range is the suggested range of Lexile measures between which the reader should be reading. The Lexile range of a reader is from 100L below to 50L above his or her Lexile measure. For example, a student with a Lexile measure of 750L is encouraged to select books with Lexile measures between 650L and 800L. This recommended Lexile range of -100L to +50L does not change according to the student’s Lexile measure, which helps to ensure that students at all levels are reading books a
