it doesnt work like a resistive screen on old PDAs or nintendo DS that needed calibration.
if its not working right you either have a film of some kind of conductive liquid or mist on the surface thats affecting it sensing your finger, or the screen has a faulty ground or something that might need to be fixed. (replacement phone)
most often I find there is some kind of smudge of grease in the corner that throws off touch sensing for the whole screen. a good cleaning with windex and soft rag fixes it. wiping the phone on the pant leg doesnt usually get it all.
well, on my Triumph with gorilla glass its a heck of a lot better. my old OV used to not clean very well with cloth