My question involves the usage of "that is." I would like to use this construction in such a way that it will provide further qualification to the previous passage or sentence.
An example might be something like this:
"However, it is far less clear whether the fluent processing of a word will have the opposite effect, that is, will the reaction time to a given stimulus show a decreased latency."
What would be correct usage of punctuation, semi-colon, questions marks etc…? Or perhaps does this type of construction not even make much sense?
Best Answer
It is acceptable to employ a comma before that is; but I would prefer a stronger disjunction, either a colon or a dash, simply to make the structure of this long sentence clearer. A comma after that is is conventional.
You do need to restructure the clause following that is as an indicative rather than an interrogative: that is, as "the reaction time to a given stimulus will show a decreased latency."