That will delay your arrival at the truth.
Until we get some chemistry in place that guarantees truth-telling in all circumstances by all people, you and I are better off using trickery, incarceration, sensory deprivation, and food manipulation to gently "coerce" truthful answers from our prisoners, eh?!
Certainly torture means any and all means for obtaining information.
I have never seen any data or publications regarding the use of torture, nor would I be likely to believe any that do exist as it does not seem that a researcher would have the option of judging torture highly effective. Nor do I think history covers these sorts of things with any accuracy. For instance, I know from a number of primary sources that German troops, especially SS troops were tortured very badly at the end of WWII, this is not spoken of generally.
So I guess I am speaking on the legality of torturing illegal combatants, not the effectiveness.