Basically this means is what is being tested actually being taught. If fractions tested on the 3rd grade standardized test, but taught in your district's 4th grade math curriculum, it's easy to see why a child might not do well. I don't have a clue how to deal with a problem like this, but you as a school administrator and your board need to understand the problem. Check to see what type of reading children are tested on. Most school's reading instruction is heavy on fiction and narrative non-fiction.
Most tests see if kids can read factual exposition.
Ask your media specialist how she is getting them into the hands of kids so they can do meaningful practice reading. Building extra time to practice skills and encourage reading practice by ALL students. It's unarguable that kids who like to read, who read willing and joyfully also tend to read better 2 . Good media programs bolster the efforts of the classroom teacher and reading teacher whose responsibility it is to teach kids how to read by helping kids want to read. Again, kids who like to read, read better because of the practice.