DYK #9: States regularly report student performance and progress in several ways, such as percentile ranks, normal curve
equivalent scores, scale scores, and proficiency status. When states do not use a vertically scaled test that ensures scores
are comparable from grade to grade, change can only be detected when students move from one proficiency category to another (e.g., from below proficient to proficient)
Tindal, G., Nese, J. F. T., & Stevens, J. J.