Most high achievement test scores are not anomalies. Still, I was more convinced that my DD's MAP reading scores were a decent indicator of her reading level when she had multiple high scores. She took the MAP test in the fall of 2nd and then again in the fall of 3rd. She stayed in the same percentile range and showed excellent growth from year to year.
DD is a voracious reader (as in it is very hard for the teacher not to notice, as her nose is often in a book when she has a chance) and she also had some very high measures in other areas (Dibbles, AIMS-Web). I think it would be hard to argue that her recent MAP scores were an aberration.
Why does your DD's school give the MAP tests? Did they provide a MAP lexile level and does this level seem like an accurate measure of your DD's reading ability? Has she taken or will she take the test again soon? If she is showing a pattern of scoring high, it would be hard to argue that the score is just "good guessing."
"Poor comprehension" is a common excuse to give to parents of excellent young readers, as to why students cannot actually be instructed at their level (implying that although they can decode the words, they do not understand what they are reading). I believe that the MAP test actually does test this and it would probably be hard to obtain that score with poor comprehension. You may want to assess comprehension on your own, but evidence of excellent comprehension can help boost your request for more challenging instruction (other test scores, WJ III Ach. Reading scores, etc.).
HTH!
