One reason why lawyers make objections is to help you, the witness, notice that something in the question makes it difficult to answer and to be careful. You should not have to answer a question that is vague. It makes it too easy for the lawyers on the other side to present your answer out of context in a brief.
If a question is ambiguous, ask for clarification. Once you understand the question, ask yourself if you really know the answer or are guessing. If you are not sure, say so.
Answer questions as clearly and briefly as you can. If you cannot answer a question in one or two sentences, something might be wrong with the question. Some of us are used to speaking in paragraphs in our daily life, but it is not a good way to testify.
You will want to be especially careful when testifying about documents. Again, ask yourself if you know the answer or if you are just reading the document. Sometimes a document says something really harmful to your company, but it might not be admissible because, for example, the author is unknown or cannot be found to testify.
Frequently, a lawyer will show a witness a document and then ask if this is a business record of the company. “Business records” are an exception to the rule against hearsay, under some circumstances.
Generally, business records are something you would refer to and rely on when making decisions. Unless you are sure something really is a business record, don’t admit that it is. You can’t assume a document is a business record that qualifies for the exception just because your company is a business and some packrat kept this juicy-sounding document.
Even the most unpleasant, harrowing deposition has to come to an end. In a federal court case, the default rule is that a deposition lasts for seven hours on the record, not counting lunch and breaks. There are exceptions, but you should be told well in advance if the deposition is expected to take longer.
When the party that asked for your depositions is finished questioning, the lawyer defending the deposition has the opportunity to ask you questions. If you have been worrying that an answer you gave earlier was incomplete or you remembered something helpful, this is a good opportunity to literally set the record straight.
What would help is a better interpretation of the phrase "jury of peers". If the subject is engineering the jury should be engineers and the court officials should be experts in the field. This incidentally is practiced in many developed countries mostly with good results ...
It is sad that we live in the age of litigation. Granted none of us engineers are as savvy as one of the ex-USA presidents (who debated what the meaning of the word "is" is...!), I do feel that many of us lack the gift of gab to explain what we mean clearly. What Brian opines above makes much sense in such circumstances.
I have one piece of advise, and yes, I have been in this situation several times. Answer only the exact question you were asked. As engineers we are trained to be helpful - stop it. don't. You wont be thanked for being helpful. Make sure you really understand the question, and don't help them to clarify it. Make them do the work until they have given you a question that you can answer with confidence.
I can only imagine the pressure on the engineer before and during questioning. Engineers like to get it right but also want to not say the wrong thing that might be twisted. I have not been involved in a patent case but would want to spend a lot of time preparing with both the source documents and practice lawyers before giving a deposition.
Anyone had the experience and would be able to comment?
re: "Even the most unpleasant, harrowing deposition has to come to an end."
Patent Litigation is Exhibit A for the case that pre-industrial decision systems are grossly inadequate for the technology-centered post-industrial economy -- let alone for the impending digital economy. The jury/legal system is a misfit in the specialized field of intellectual property, by denying that intricate technology issues require seasoned judgement of experienced specialists. What is needed is technology-centric processes that help achieve the economic benefits from inventions and innovations, without getting mired in unproductive legal procedures.