I use an ecollar as a form of correction with no side effects. In fact, it is the only thing my dog responds to. I can prong him until the cows come home when he is in drive and he doesn't even feel it. That's just the way he is and I have no other choice. My female on the other hand responds great to a prong so I would probably use Peter's theory with her. I may end up using it for a few exercises to pick up her speed. For example the sit and down in motion it works excellent for! I really had good results getting a quick sit and down with Rosco using the ecollar. I think all dogs are different and require different types of training. I would love to be able to train a dog without the hassle of using an ecollar but unfortuantely without it I would be screwed with Rosco. Of course I need to get him working without it eventually, but the same can be said for people who train with prong collars as well. Its a training tool and just like all others need to be approached with common sense and fairness.