I was having problems with hanging shifts, both upshifts and downshifts, with my Shimano 105 9 speed drivetrain. I had gone through everything else, cables, cassette, chain but it still wasn't shifting right. The only thing left to do was to align the derailer hangar, and I was just about to take it to the shop when an idea struck me. Since the hangar has to be in a plane that is parallel to the plane that the seat tube is in, all I have to do is use a spirit level to measure.
So I put the bike in the stand, put the spirit level on the seat tube and shimmed up the stand until the seat tube was vertical. Then I laid the spirit level on the derailer hangar, and sure enough, it had been pushed in. So I used my BFAW (big f@cking adjustable wrench) to grasp the derailer hangar and bend it out. Now it shifts perfectly, at least on the stand. Tomorrow I'll try it on the road.