I happened to be volunteering in DS7's class today and saw some paperwork showing my son's lexile reading level. I was curious as to what it means so did a google search, but every site shows the number as correlating to different "grade level". Some sites differ by more than 100 pts. Does it vary by state? Is there a standard?

His level was 10??-12?? (can't remember the exact numbers). Some sites show that as 6th grade level, while others show it as 9th or 10th.....