I just post current work from all grade levels. This includes pictures which I take with my phone of kids singing and playing instruments; I put captions underneath explaining. For example “In October PreK and Kindergarten are learning to keep a steady beat on instruments and in their feet.” Yes, it’s possible to display assessment data from each grade level … easier the more often you see your kids. Kids love seeing themselves or their friends in pictures. ….But if data is what they want, I say give it to them. Don’t reinvent the wheel. Criteria could be as simple as Yes or No students have / not yet mastered the skill.
I am regularly discouraged that we specialists are handed the same list of requirements as teachers who see their kids all day long. I see most of my kids once a week for 35 minutes. Formal assessments don’t happen … er, as often as they should because of this time limitation. Most of my assessments are aural / personal notes. I know where my kids are; it just takes a ton of extra time to prove it.