The Symphony assessments were constructed and validated using students from all over the United States. To obtain national norms, the Symphony scores of samples of New York and Illinois students were equated to the National Assessment of Educational Progress (NAEP), using the New York and Illinois state tests as a bridge. These states were selected because their state performance on NAEP is very similar to the national average. Having this bridge allows us to express students’ performance on Symphony mathematics in terms of national percentiles.