No Child Left Behind is the federal legislation that requires improved performance by students in each school and real consequences if improvement does not occur. Some schools will always score higher than others, and that does not mean it is a better school. Some schools have a student population that scores higher for a variety of reasons.
Instead, I encourage you to think about this- the real key to your child's success in school is related to his/her teacher. The person who teaches your child every day is the key to education, and if your child has a really good teacher, you should be very, very pleased.
Bottom line- school level performance is important, but the quality of your child's teacher is far more important to success.
You don't say what State you are in. You don't know if you have public school choice unless you contact your school administration. BTW, check those scores locally to see if they have gone up since the last time they were posted her.