Those places are full of nice dogs. And those people know them best and are able to match up the personalities of the dogs and people.
I see people in tears, not wanting to give up their dog but not knowing what to do anymore.
The success is based on canine and owner participation. The only owner I can't train is one who doesn't want to learn ? and that's unfortunate for the dog. A lot of the dogs are turned over to shelters because most people haven't come across a training technique that works.
A lot of people feel that if a dog has nipped, growled at or bitten someone there's no hope for that dog. Nearly 99 percent of the time a dog like that can be turned around if an owner is willing to work with it.
A lot of people are good people leaders, but dogs think differently than humans do. When we treat them the same as humans, many times we get the opposite effect of what we're intending.
It's like hiring a sitter. Interview those people to find out if their techniques are in line with your own thinking and if they're qualified to handle your 'family member'.