Refs should be constantly reviewing and discussing prior decisions with each other, weekly ideally, but at least every month. Almost like how law follows precedent. If a ref gave handball for a ball popping up in the air from 1yard away and he has no time to react, other refs when reviewing that decision should either call it as being an incorrect call, or back him up and all go with that decision. Right now, they all seem to be able to do what they like as long as it's their interpretation of the rules because, as pundits say, that's "part of football" or, "that's what makes football football" (load of ****)