Yeah, I think using another data source for hospitals would be better, I'll look into using supplemental data as the other comment suggested.

I suspect that hospitals are better represented than other POIs because their building footprints are large and distinctive, allowing them to be mapped from aerial imagery.

I limited this analysis to facilities providing inpatient care to avoid that problem. I suspect clinics are less accurate POIs. They're pretty much indistinguishable from other retail businesses from aerial imagery alone.