Scout 'snuck off' twice after she was six months old and took a poop on the dining room floor. I knew it was her and not the cats because she wasn't eating it....
I just had her outside on both occasion, but apparently not long enough. Puppies go alot more than an adult dog. Also, like the posts before me, I know when and how much both of my dogs go to the bathroom. For example when I get up for work in the moring at 4:30 am, I know that she is due for a poop. So we wander around the yard, usually she is pretty fast maybe five minutes. I can't tell you how many times I've stood outside with an umbrella, or in the howling cold wind waiting. She pretty much goes on command now. She knows the routine. She will be 11 months old on March 5.
Just keep being consistent. That's the most important part. Remeber they are very fast.
Sharon, proud Mom of Scout (tri) and Breeze (Newfie)