I can tell you from experiance it works. Trinity use to be all over the place and it felt like she was going to rip my arm off. I started using a prong collar because nothing else worked. Well after about a week there was noticable change. She wasn't all up in peoples yards she didn't pull it was great. I actually like taking her for walks now. LOL I don't always use the prong collar though cause after about 3 months of putting it on her to take her for walks I slowly backed off. Like the days I didn't put it on her I would still bring it so she would know I would have. Kind of like telling her " Don't make me put it on you". She doesn't really need the prong collar anymore. The only times I have to put it on her is when I don't walk her for awhile.