Dog scratches at the doors to get in or out

Question
My dog has ruined doors. She scratches on the wood work around doors to get out (mostly when we are not at home) but will scratch at the door itself when she wants to come in. She is ruining doors. I want to stop her of this habit. I can kennel her when we are not home to prevent her, for the most part, on the inside destruction but cannot seem to prevent her from jumping and scratching at the door when she wants to come in. I need some advice and hopefully you can help me. Thank you!

Answer
Use positive reinforcement training to teach your dog one basic behavior: "sit" (but use a different word.)  To learn about this sort of training, see: ClickerTraining.com.

Once the dog has obtained a conditioned response to this word, make her EARN going OUT and coming BACK IN by "sitting" first.  This will interrupt her motivation: she will learn (this will take a couple of weeks after she has obtained a 100% reliable response to your command for "sit") that she CANNOT come back in until you command her to "sit".  This breaks a chain of behavior: right now, dog scratches and you PAY ATTENTION (and most likely let her in) thereby REWARDING the scratching; once the dog has learned (by repetition) that "sit" is required BEFORE she comes indoors, the chain of behavior will have been interrupted and she will stop scratching.  HOWEVER, you cannot let this dog remain outdoors for more than a fair amount of time. The scratching at doors from inside when you are not at home is BARRIER FRUSTRATION, a sign of separation anxiety, and this sort of anxiety will be present if the dog is confined outdoors unfairly and kept away from her people.  You must leave her outdoors ONLY for the purpose of elimination (unless you are out there with her) and be VIGILANT about it (don't forget she's out there and go fold the laundry!)  If you do not, she will lose the behavior change acquired at having to "sit" to get back indoors.