This isn't longitudinal data, just the grade by grade snapshot from October 2009. Not enough to make any kind of super-precise analysis, but it is hard to look at those graphs and say "Yeah, we should close Highlander."
I'm not sure what's up with the 3rd/4th grade dip, but to be honest, as a parent in Elmwood, I'm not that worried about elementary school, and the reason a couple PPSD elementary schools are at or above Highlander is there are some very good elementary schools here.
It is middle school that keeps parents awake at night, so closing a K-8 school that's doing very well in the later years because of some elementary school dips is just perverse. The reason Greene middle school (light blue) has such high scores is because it includes the district gifted program.
Looking at the charters, there's not a lot here to make the other local charters feel very secure. If Highlander is going, any of them conceivably could with some bad luck.