What are the letters in front of the Lexile measure (AD, NC, HL, IG, GN, BR and NP)? Lexile Codes
This is a Lexile code. It gives you more information about a book that relates to its developmental appropriateness, reading difficulty, and common or intended usage. Sometimes a Lexile measure by itself is not enough information to choose a particular book for a particular reader. See our "Lexile Codes
" topic for detailed definitions of each code.