I agree with wadeintothem, at least at the higher levels the catcher does make a difference. It is a matter of survival if she catches it, more will beleive it a strike. With a good catcher you mention something like "man if you catch that I can get away with calling it a strike" now some will say that is giving the catcher a feeling that your zone is weak or you are guessing. I say that is having a good conversation with your best friend during the game. A good catcher will adjust and either bring up the pitch a little or she will make darn sure she catches the next one. I know technically that is not in the rules, so Cecil is technically correct, but if you have this small conversation early it makes thing much easier on everyone! And we are talking about 2 maybe 3 pitches a game....if the pitcher is smart she adjusts a little bit to my zone, out of 180 that we call (average of 89.6 pitches per game in college according to a study I read, so it is probably more in HS and youth) if you are 99% accurate you miss a couple a game!
Also the outside pitch, if the catcher moves her mitt I am going to have a talk with her, just her and I will know we talked, something like, "wow that was on the corner, but you know how bad it looks when I call that after you jerked your mitt inside? hold it still and I will bang that all day long" Again 1 or 2 pitches on a team(pitch and catch) that know what they are doing is all it takes. I notice it on girls that have a good curve, start inside and grows outside, if you call the plate (which I try to do
) by the time the ball gets to the catcher it might be a foot outside (still a strike....Ok maybe not
) if she holds, even though she caught it outside I know where it crossed the plate, and I will take the heat over her catching it outside vs her moving the mitt to "trick" me. Again maybe there aren't rules to support me, but on a pitch that close my judgement put it out of the zone if they move, or drop it and into the zone if they don't!