Charles Arthur, in Guardian:

Why does NPD ignore the iPad, though? It’s the tablet that is actually selling well. Comparatively well. And as Gruber also points out, the whole “76% of consumers who purchased a non-Apple tablet didn’t even consider the iPad” is a meaningless statement until you know how many consumers did buy an iPad. Then you find that it’s 76% of 11%, or 8.3%. Which means that even among the people who bought a TouchPad, at least half considered the iPad first.

Clearly, people in the US who buy tablets tend to consider the iPad in their purchasing decision.

Analysts can’t figure out iPad sales, pretends it doesn’t exist