Old dog learns "new trick" too well

I have a 13-year old Shih Tzu that started having some issues with relieving herself in the house instead of outside. In order to modify her behavior, I started giving her a positive reinforcement (dog treat) when she asked to go out and successfully used the yard instead of our floors.

This had immediate success however, she soon started asking to out more and more frequently, ostensibly to get the next treat. I have tried to offer the treats only on a random basis. This has had the effect of her asking more frequently to go out since she is "playing the odds" if you will.

In addition, she still has times where she uses the floor in the bathroom. We have an obsorbent pad that she uses so it is not a bad problem. We still would prefer that she go outside but she sometimes neglects to ask and just uses the pad.

What did I do wrong and how do I re-teach her to get her to use the outside only.

-Jim In Buffalo

Hi Jim,
Since she was previously housetrained and this behavior has recently started, have you had her checked out by a vet? There may be an underlying medical cause. It could also have to do with her age and memory, although 13 is hardly elderly for a small, otherwise-healthy dog. Another thing to ask your vet about. Once you've determined there is no medical issue causing the recent issues, some other questions to think about:

Is she crate-trained? This could be an effective tool if she goes in the house when you are not there to supervise. Personally I'm not a fan of paper/pad-training; it seems that once you've taught a dog that it is okay to go indoors anywhere, it is significantly more difficult to re-train them to only go outside.

When are you offering the reward for going outside? After she has asked but before she has done her business, or after she has successfully completed her business? Some of her "playing the odds" might have to do with her not really understanding WHY she is getting a reward, depending on the timing of the reward (is the treat for sitting by the door, or is it for relieving herself?) Wait to reward until immediately after you have seen her relieve herself - yup, you might have to follow her around a bit with a good treat in your pocket. If she asks to go out but then just wanders around and doesn't do any business, or sits to go out but then loses interest in actually going outside once she has your attention, just offer verbal reinforcement ("Very nice, good girl.") but no treat or toy until you have actually seen her do something. She may continue to pester you a bit at first but she will eventually figure out what you want.

Finally, in the event that this is an aging-dog memory problem (some dogs do seem to forget or lose some of their training with advanced age), go back to housetraining basics - if you do not want her to relieve herself in the house at all, remove the pad. Without making a big deal out of accidents, clean up immediatly with Nature's Miracle or a similar scent-neutralizing product. Keep her tethered to you or in a small, easily-supervised area when you are home so you can watch for sniffing or squatting and immediately redirect her outside. Consider crate-training if she must be left unsupervised.