Wouldn't it be nice if there was a good track record of handlers training their own service dogs? Unfortunately, it's been estimated that only 1% owner-trained dogs work out. This number begs the question, "Why?" Why does it take a whole organization to successful train a service dog? There seems to be three reasons why the nonprofit system with professionally-trained Service Dogs is the one that works:
Only 1 out of 1000 dogs is appropriate to be a candidate for training. That's our estimate, but personal conversations with trainers from three different nonprofits confirm that this figure is about right.
It's emotionally difficult to "fail out" the 50% of candidate dogs that inevitably wash out.
The handler has to deal with both their disability and the selection, evaluation, and training of the dog.
I think this is why the Americans with Disabilities Act doesn't have a federal commission for certification of service dogs. Since it's so hard for even experienced service dog organizations to select, evaluate, and train a dog, why make it even harder with more regulations? That’s also why there is no official certifications for organizations that train service dogs. Note that the U.S. Congress has tightened up the rules a bit by focusing on the definition of “disability” and setting the bar pretty high, such as “unable to perform a major life activity that the average person in the general population can perform,” and then defining “major life activity” as “functions such as caring for oneself, performing manual tasks, walking, seeing, hearing, speaking, breathing, learning, and working”.
 "The Problem with Owner Training." Service Dog Central. Accessed May 1, 2071.
 Personal interviews: Mutts with a Mission, April 2014; Dog Services, March, 2015; Dogs for the Deaf, January, 2017.
 "Service Dog Selection Tests." Emily Weiss and Gary Greenberg, "Applied Animal Behaviour Science 53, no. 4 (1997): 297-3.
 FSIS Directive 4306.2, "Reasonable Accessibility and Accomodation For People with Disabilities," USDA Food Safety and Inspection Services.