Jennifer James of Chapel Hill, North Carolina, admits that her oldest daughter can sometimes be a handful. When all else fails, Jennifer finds herself blurting out, "Wait until your father gets home!" But, says the mother of two, "I feel so powerless when I use that threat. I wonder why my daughter is afraid of her dad finding out about her bad behavior but feels right at home acting up around me."

The answer may lie in Jennifer's choice of words. While it's easy to rely on timeworn phrases of frustration, the truth is that the more you use them, the more likely your kids will tune you out.

Here are five expressions of exasperation that won't get you the good behavior you want, and more effective methods that will.

1. "Because I said so, that's why!"
Is this your answer in the nightly battle of "Why do I have to go to bed?" and other questioning of your authority? Your child might naturally respond, "But I want to stay up later!" and the verbal volley could go on forever, notes Gina Richman, Ph.D., director of the Child and Family Therapy Clinic at the Kennedy Krieger Institute in Baltimore. He deserves a valid reason, whether or not he agrees with it.

But be prepared. Giving an explanation may prolong the conversation as children try to find loopholes in your logic, says Dr. Richman. "You're also giving them hope that they can change your mind. So you must close the door to any further negotiation. You can say, ‘You have to be well-rested for school tomorrow. That is the reason. The discussion is over. If you persist, there will be consequences for not listening to me.'" By making a rule and having a valid reason for it, you are teaching your child to be responsible, adds Dr. Richman.

2. "Wait until your father gets home."
Like Jennifer James, many mothers wonder why the mere mention of dad's name strikes fear in the hearts of their kids. But mom? No need to worry. She won't do anything. "What you're saying is, ‘I have no control over your behavior,'" explains Dr. Richman. Your child gets the message that she can do whatever she wants when mom's around.

You need to regain your authority. First, understand that consequences—whether a time-out or other restrictions—need to be enforced immediately to make a difference. Both parents should set down the rules. "Then dad can add that ‘Mom needs to call me at work if you're not doing your homework,'" says Dr. Richman. "Make clear that mom will ask once, then if dad has to get involved, that's the child's choice." As you resort to calling dad for backup less often, you regain control.

3. "Don't make me come in there!"
Instead of shouting this meaningless threat when you hear your youngsters bickering in another room, ask yourself, Can I stay out of it? advises Dr. Roberts. "Let them learn to solve their own problems by talking."

What if their squabble escalates to name-calling or hitting? Enter the room quietly and don't bother asking pointless questions like "What's going on?" or "Who started it?" Just separate the children and give each a time-out.

Once your children have calmed down, be clear that you will not allow them to be abusive or to belittle each other, then discuss other actions they can take to avoid problems. "Talk about what can be done differently next time," suggests Dr. Roberts. The message you're sending is that they need to learn how to handle disputes themselves.

4. "Money doesn't grow on trees!"
Do you find yourself saying this at the mall as your youngster begs for the latest Bratz doll or Game Boy cartridge? "That isn't the time to have this argument," says Edward Christophersen, Ph.D., staff psychologist at Children's Mercy Hospital in Kansas City, Missouri, and author of Parenting That Works: Building Skills That Last a Lifetime (APA Books). He recommends setting limits before you leave the house. Let your children know ahead of time what you will, and won't, be buying for them. If you're consistent, eventually they will stop asking you for extra things.

Also teach kids what it means to be fiscally responsible. "Don't just give them an allowance. Have agreements on how they earn it and how they spend it," says Dr. Christophersen. Once their spending money is gone, don't supplement it.

5. "How many times have I told you...?"
It doesn't matter how this sentence ends. Most children respond to it the way Eric James, 9, of Clifton, New Jersey, does: With an eye roll and a smart-aleck answer. This frustration phrase—all of them, in fact—is a poor and typically self-defeating attempt to shape children's behavior, says Denis Donovan, M.D., medical director of the Children's Center for Developmental Psychiatry in St. Petersburg, Florida, and co-author of What Did I Just Say!?! (Henry Holt). "What the parent really wants is the desired behavior, not a verbal response, and especially not a smart-alecky one. Unfortunately, parents confuse the issue because, for them, each of these phrases has a conventional meaning, which has little, if anything, to do with the literal meaning."

If you pay attention to what you actually say to your kids, you'll be stunned by how rarely your words correspond to your intentions. "For example, if you say, ‘Hit your sister and see what happens to you!' don't be surprised if Billy hits his sister," warns Dr. Donovan.

If you want your kids to truly process what you say, you must be direct. If you ask a rhetorical question or make a principled statement instead of issuing a command, it allows your child to logically dismiss what you said, nail you on technicalities, or not even consciously register what you said.

A better approach? Say what you mean and mean what you say, Dr. Donovan advises. "If you want action, say, ‘Stop kicking your brother's chair,' or ‘Put your toys in the toy chest.'" If you are truly uncomfortable with such directness, preface it with a "Please." You'll certainly be pleased with the result.