In the dog training world, "correction" has a special meaning.  What the term means depends very much on who you ask.  As I learned it, a "correction" doesn't really "correct" anything at all.  It just stops my dog from doing something I didn't want.  How does a yank on a leash or a poke in the side tell my dog anything about what I want them to do other than stop what they are currently doing?  Perhaps that lack of information can be detrimental to my dog!