Warschauer's research explicitly refers to a number of other individual characteristics:


gender (only 2 men)


age (only age range given)


length of residence in US


number of years studying English


proficiency in English


fluency in conversation


typing ability


familiarity with computers


'attitude' to cmc


and, there are also 'personality' factors.


In fact, Warschauer randomly assigns participants: this is pointless as comparability of groups is unachievable


And, Warschauer fails to provide coordinated data:


We do not know the composition of the groups in terms of individual characteristics:


We do not even know the coordination of individual characteristics (eg what nationality were the two men?)

from: Warschauer's sampling

to: Warschauer's findings