Don't pay attention to test scores alone. Many schools fail miserably on a broad scale because the ONLY thing they are teaching is the bare minimum to achieve exactly what's on the tests. This is a major national problem right now. My friend teaches high school in a very highly rated (test scores) school, but has seen the student body PLUMMET in comprehension and critical thinking in the past ten years. According to her they don't know how to think independently, and they always want to know the "right answer" even on questions that specify, "Use your imagination". Cursive has been cut, social studies, art and science have all been cut to practically non-existent. Math comprehension and mastery is way down. Lots of things aren't being taught, but the "test answers" are taught and the school has a high rating.
I researched what a thorough education would look like internationally and from times when America's schools were highly rated globally. (50s-70s). You can find Classical Education guidelines (if you want the standard "all subjects taught in traditional schools" approach) and then find out what the school is teaching by meeting a teacher in the grade you're interested in. A super simplified version of this is the "Core Knowledge Series-What your Kindergartener, First Grader, Second Grader....Should Know" books. I took in a Kindergarten outline from The Well Trained Mind for Kindergarten and First Grade and the Core Knowledge Book info for those years and interviewed our local school to see what they would be covering in kindergarten and first grade: HARDLY ANYTHING. (and it's a very lowly rated school in a bad district so fair enough). Soooo, we're in our second year of homeschooling and my daughter is way ahead for first grade and loving reading ravenously on her own about the ancient Greeks, she's in an advanced math program and loves human body systems.. and she also has time for piano, violin and Tae Kwon do and French-all things people say are "frivolous and unimportant" in our town, but meanwhile, it's standard for kids in other countries to have those things in kindergarten. Our Australian friends have daughters learning violin and Mandarin AT SCHOOL in kindergarten. We have German, French and Canadian friends, all of which have second languages and instruments for their kids in early education.
A high rating for your state is a good start. Maybe the school is complete in all subjects with enough individual attention for students, and a high standard instead of keeping the entire class in step with slowest learners.. if so, your kids won't be behind any kids in your state. But dig deeper to see if you feel their education will be thorough enough for their future opportunities and then act accordingly. Asking other parents with kids in the school is not helpful. Any parent at any school they've decided to use pretty much says "My kid loves it, it's great" and that's really pretty meaningless if there isn't enough being taught there compared to schools with great educations.