How do I calibrate my touch screen on Lollipop version?

[AC Question]

The left upper corner of my screen - where you tap to go back in Message as well as Gmail, etc does not always register my tap since upgrading to Lollipop - I would like to start by calibrating my touch screen (or gyroscope I guess it's called) however since upgrading to Lollipop, I cannot seem to find the area in which I can do this. I know I used to be able to go into Settings and under My Device accomplish this - but it must be buried somewhere else now. Any help/suggestions would be appreciated.