Now I don't teach grades 4 - 8 ELA & Math, so this doesn't directly apply to me. But the NYC DOE places high students into one of ten groups (called deciles) based on their Eighth Grade assessment. It then assigns each student with his or her corresponding 'decile' number. You can see a full description of what deciles are and how they are compiled on pages 17 - 18 of this document. But the point I'm making is this: High school students are already grouped the way this video describes (by demographics and student assessment) so everything you're about to watch can easily be transferred to a high school teacher's Measure Of Student Learning.
Growth Scores Explained from EngageNY on Vimeo.