'Truth value" is another term in philsophy (logic of propositions) -- 314,000 hits for ["truth value"+proposition]. It's also used in speech act theory.

It's almost synonymous with 'factuality' in your previous question, and as I answered there, the more usual way to say it is that the speaker assumes/does not assume "responsibility" for the truth value. It is called "epistemic responsibilitiy."

**There cannot be an absolute truth-value to any given proposition, ... Does this relativity imply that epistemic responsibility does not exist ?** Not at all. ...
www.strongatheism.net/library/philosophy/inadequacy_of_epis...

Proof in Proposition Logic
The next step is to **consider the truth value of the complex proposition** of our example under all of these possible assignments of truth values to the basic ...
www.rci.rutgers.edu/~cfs/472_html/Logic_KR/proplogic_proofs...

Yet, **only if the speaker knows in advance (almost a priori) the truth-value of the relevant proposition** can he identify it in this way. ...
links.jstor.org/sici?sici=0031-8248(196404)31%3A2%3C173%3AITAT%3E2.0.CO%3B2-D




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Note added at 6 hrs (2006-11-13 23:33:30 GMT)
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It's often written with a hyphen: 'truth-value'