I don't believe user interfaces could be evaluated in such a quantitative and useful way, as you describe. You could slap some number in there, but that doesn't

I don't believe user interfaces could be evaluated in such a quantitative and useful way, as you describe. You could slap some number in there, but that doesn't make it useful. Bear in mind that the UI itself is just a part of the equation, alongside the user and the usage context. Two identical UIs (evaluated at about the same score with the hypothetical UIQC) can perform radically different in the hands of the end-user, because the users and their contexts are different.