Assume the worst: that a critic will ask you the one question you would rather not answer in public. “Isn't it true that you were convicted of stealing ten years ago?” or “Why does your company have the highest number of sexual harassment lawsuits in the state?” If there is a formal, written response available, summarize the main points and offer to e-mail the full document. If you cannot talk about it for legal reasons, say so, but provide a reassuring statement about concern for the important matters at issue.

Never duck a tough question. Give the best answer you can think of and bridge to a related topic that is your strong suit.

Never give an answer that is not honest. Someone in the audience may call you out and your credibility and the effectiveness of your speech will be destroyed on the spot. If you really do not know the answer, tell the questioner that you will need to do research and get back to him. Audiences will tolerate humility in ignorance, but not arrogance. Or you can ask if anyone in the audience knows the answer: this can make that person look smart without this being at your expense, since no one else probably knew the answer, either.

On the other hand, if someone clearly has an in-depth knowledge of the field and disagrees with you, you can simply state that the experts you rely on have a different consensus and note that there are usually disagreements among experts in any field.

Sometimes you may be asked a question based on a false premise: “Have you stopped beating your spouse?” Stay calm and state that you are going to clear up some obvious confusion about the facts in this case.

Another problem can be the highly hypothetical question: what if the entire management of your company was to die in an airplane crash? If there is something concrete to say, state it (“management never flies together”), otherwise just tell them you are not authorized to speculate on far-fetched scenarios and pick the next question.

You can also get into trouble if someone asks you to do a ranking: which are the best hockey teams in the nation? How would you rank the candidates' comparative intelligence? You can answer ratings questions that are legitimate and safe to answer, otherwise just tell the audience that you really do not have an answer off the top of your head.

You may also face a question based on trying to compare your product or service and another unfairly. You can deal with this one by noting that it is an apples-and-oranges comparison and then restate what is unique about yours (“we are the only union for bartenders in the state park system, so what bartenders earn in major cities is not relevant”).

If someone wants to rant about a pet peeve, the host should break in to ask what the question is. Or you can interrupt to thank him for sharing the information, but note that others in the audience need to be given time to participate.

If a member of the audience challenges your credentials, you should be prepared to calmly take the opportunity to tell the audience something it did not already know about your background. The introduction may have mentioned your degree, but did not say that you worked up from mail room to management in the industry and have an insider's understanding of it based on hands-on experience. Or you may have written articles for a professional journal. Or you became interested in the disease you are talking about when your mother fell ill and you interviewed top specialists in the field to find out about cutting-edge therapies.

Do not get down and dirty in a serious argument. If your speech did not convince the skeptic, no Q&A exchange is going to do it. Just restate the main reasons you hold to your position and move to the next question. Treat each questioner with dignity. Never attack anyone and never embarrass him, even if he tries to do it to you. Stay centered and you will impress the audience with your self-confidence.