Thanks, Xander. I think I can tease out the most recent report using max(date) but then I need to compare it to the second most recent report. Since I can't just say "yesterday" (reports don't happen every day), I'm stuck there. I imagine it must be possible to sort the dates somehow and choose the second most recent to use as a reference to compare to the most recent. I just can't seem to figure out how that would be accomplished in arcade. Maybe I have to do this calc on the backend with Python? I was hoping to avoid schema changes though, if I can.
Update: Now I see what you mean with the indicator. It has built in field {} calcs that refer to the previous value. That in conjunction with conditionally formatting for increases and decreases will work fine. Thank you!