The 80-20 rule in dog training is also known as the Pareto principle, which states that 80% of your dog's behavior comes from 20% of its training. In other words, the majority of your dog's behavior is a result of the most important and fundamental aspects of its training. For example, if you focus on teaching your dog basic obedience commands such as "sit," "stay," "come," and "heel," these behaviors will form the foundation of your dog's training and behavior. By focusing on these fundamental behaviors, you can address and correct a majority of your dog's unwanted behaviors. The 80-20 rule is not a hard and fast rule, and each dog is unique and may require different training approaches. However, by focusing on the most important aspects of your dog's training and behavior, you can achieve significant improvements in your dog's behavior and overall obedience.