The state of New York has a formal examination process at various grade levels. You cannot graduate from high school in New York until you pass your Regents exams.
There are a lot of complaints about that process, but it does provide an accurate indicator of a school's performance because just about 100% of the students take the exams.
All states have to impose standardized testing under Dubya's "No Child Left Behind" law. And the educrats hate it. Check this
thread..
For years, the only thing that came close to a way of comparing achievement between states and districts was SAT scores.