Interrupt mistakes as they are happening. Don’t be too harsh or your dog will be afraid to go in front of you, which simply results in a dog that waits for you to be absent and goes potty in the house secretly. Make a noise that is meant to startle, NOT frighten.
After interrupting your dog, hustle him outside to the potty area. Praise if he finishes there.
If your dog made the mistake one hour or five seconds ago, you are too late. It is often tempting to scold or correct a dog for finding a mess planted on the carpet while you were away at work. Your dog, however, lives in the moment and will have long ago moved on from the act of unintentionally ruining your furnishings. He will have no idea what you are punishing him for and will start to see you as an unpredictable force worthy of fear. Just as in reward training, the result (either reward or punishment) must occur within 0.4 seconds of the behavior – otherwise it is pointless and ineffective. Enough punishment can lead to a dog that feels anxious and fearful every time they feel the need to eliminate, sometimes causing them to resist their urges to the point of developing urinary tract infections. You must catch him in the act for the interruption to work, and again, you can’t do it too harshly or your dog will be afraid to go in front of you.