In the 1980s veterinarian and animal behaviourist Ian Dunbar discovered that despite evidence on the peak learning periods in animals, few dog trainers worked with puppies before they were six months old. Dunbar founded Sirius Dog Training, the first off-leash training program specifically for puppies, which emphasizes the importance of teaching bite inhibition, sociality, and other basic household manners, to dogs under six months of age. Dunbar has written numerous books, and is known for his international seminar presentations and award-winning videos on puppy and dog behavior and training.
The concepts of "pack" and "dominance" in relation to dog training originated in the 1940s and were popularized by the Monks of New Skete in the 1970s. The model is based on a theory that "dogs are wolves" and since wolves live in hierarchical packs where an alpha male rules over everyone else, then humans must dominate dogs in order to modify their behavior. However, recent studies have shown that wolves in the wild actually live in nuclear families where the father and mother are considered the pack leaders, and their offspring's status depends on their birth order which does not involve fighting to attain a higher rank, because the young wolves naturally follow their parents' lead.
Lindsay says of this study, "Schilder and Van der Borg (2004) have published a report of disturbing findings regarding the short-term and long- term effects of shock used in the context of working dogs that is destined to become a source of significant controversy ... The absence of reduced drive or behavioral suppression with respect to critical activities associated with shock (e.g., bite work) makes one skeptical about the lasting adverse effects the authors claim to document. Although they offer no substantive evidence of trauma or harm to dogs, they provide loads of speculation, anecdotes, insinuations of gender and educational inadequacies, and derogatory comments regarding the motivation and competence of IPO trainers in its place." 
Unfortunately, there is no magic length of time or milestone age when a puppy can be considered fully housetrained and there are many factors that go into how quickly a puppy can be potty trained. Your puppy’s age plays a major role during the initial phase of potty training, as a very young puppy won’t have the muscle control necessary to hold it for long periods of time.
If I take my pup out at 10 a.m. and he takes a 30-minute nap in his crate, that would put us at 10:30 a.m., which is 1 ½ hours away from his next scheduled potty break. So, instead of taking him out, I will place him in his crate until 12 p.m. and then let them out of his crate to go potty. I do this each time the scheduled potty breaks fall out of line with the schedule – with the exception of after eating or drinking water.
There also behavioral issues that can interfere with successful training. Urine marking is a normal dog behavior in which the animal will hike their leg and mark a certain area or object. With separation anxiety, the puppy may have accidents inside when you leave them at home alone. Some puppies become nervous or upset when their owners are away. Other puppies have a submissive or excitement urination problem. This causes them to spontaneously urinate during certain activities. Discuss these possibilities with your veterinarian or trainer if you're not getting positive results.
Unless you plan to keep your dog outdoors--and few of us do because it's not recommended--you'll need to teach your dog where to eliminate. Therefore, house training (also called housebreaking or potty training) is one of the first things you need to work on with your dog. Crate training can be a very helpful part of the training process. This includes house training as well as many other areas of training: