Even though counsel is thoroughly prepared and very well versed in the subject of the expert's testimony, he must not adopt the attitude that he knows more than the expert. In the eyes of the triers of fact, the lawyer is only an advocate and the witness is the expert. The attorney should never use the right of cross-examination merely to demonstrate his knowledge of a technical subject. In his argument at the conclusion of the evidence he can attack the expert's opinion, but even then he must base his attack on the testimony given in the case, not on his own knowledge of the subject.
The lawyer should word his questions to the expert carefully to avoid giving the impression that he thinks his knowledge is superior to the expert's. Rather than starting a question with the phrase, "Isn't it a fact that . . he should begin, "Is it a fact that. . or "Am I correct in stating that. . . The jury may thus get the impression that the lawyer is well versed, although he has not adopted an attitude of superiority.
Reasonable Prediction of Answers
Counsel should never ask a question unless he either knows what the answer will be or is reasonably certain that the answer will not be injurious to his case. Over- zealousness can destroy an otherwise effective cross- examination, as the following example illustrates.
Examining On Qualifications
Knowledge and Experience
When an expert is called as a witness, the direct examination generally begins with interrogation about the witness's qualifications as an expert. Counsel who will cross-examine has several courses of action open to him at this point. If he knows that the witness has a long list of qualifications (degrees, training, citations, and experience), he should offer to stipulate that the witness is qualified. If the offer is accepted, he avoids having the list of enhancing degrees and honors read to the jury. For this very reason, opposing counsel may refuse the offer. The attorney then must decide whether he will conduct a voir dire examination of the witness's qualifications or will forgo this interrogation, attempting to indicate that the opposition added nothing to counsel's offered stipulation and merely wanted to stress the witness's qualifications.
If the witness's background is impressive, the voir dire examination will only emphasize it, so counsel should wait and attack the witness's personal experience or the basis for his opinion in later cross-examination. If the witness's qualifications are questionable, how ever, interrogation to develop this is warranted.
Interest in Case
It never hurts to develop the expert's interest, financial or otherwise, in the outcome of the case. Some questions counsel may ask are:
Q. By whom are you employed?
Q. Were you paid for the research and preparation you did in order to be a witness in this case?
Q. How well do you know the party in whose behalf you are testifying?
Q. You have been sitting with opposing counsel here for several days. Are you being paid a per diem for your attendance?
Q. Were you paid for your appearance here before you testified?
Q. Have you a contingent financial interest in the out come of this case?
Specific Helpful Questions
Even though an expert has unimpeachable qualifications, there are certain exploratory questions the examiner may ask with little danger that a damaging answer will be given. Here are some of them:
Q. What personal experience have you had with the matter on which you have expressed your opinion?
Q. How long has it been since you have had any personal experience with the matter on which you have testified?
Q. In a specialized situation such as this, do you handle the case personally or do you refer it to a specialist on the subject?
Q. Do you base your opinion on what you have read and studied or on your personal experience or both?
Q. Have you had any special training or experience in the particular subject, or is your answer based on training and education that only incidentally covered the subject matter on which you have given your opinion?
An affirmative answer that the witness referred to, considered, or relied on authoritative texts and his naming of them are important for use of the texts on cross- examination. The answers to these questions will not add to impressive qualifications the witness has already given and may detract from them. For instance, in a case dealing with the cause and effect of a compound fracture of the skull, a university anatomy professor gave most damaging testimony. On cross-examination when asked some of these questions he admitted he had been a medical professor for 20 years and during this time had never been called on to treat a skull fracture. In another case, concerning the heart condition of a person who had died, a doctor gave his opinion on the severity of the condition and the cause of death. On cross-examination he was asked whether he was a specialist in heart diseases and he answered that he was not. He was then asked what he did when one of his patients developed a heart condition, such as a coronary occlusion, and he answered that he sent the patient to a heart specialist for treatment. The benefit the cross- examiner derived from this line of questioning is obvious.
Use of Counsel’s Own Expert
If possible, counsel should have his own expert sitting with him when he cross-examines an opposition expert. This has many advantages. The expert can suggest questions for the lawyer to ask or a course of examination for him to pursue. The expert's presence may have a psychological effect of inestimable value on the witness under examination. The witness may be more conservative in giving his opinion and may refrain from stating erroneous or unproved scientific "facts" or giving snap opinions.
If the witness testifies to matters on which counsel originally found no need to prepare, his own expert can quickly advise him or, if a fuller discussion is required, alert him to request a recess, or adjournment of the trial until the next morning (unless a lunch break is imminent and sufficient), during which he can gain enough information to conduct an effective examination.
When Counsel’s Expert is Absent
If the lawyer is confronted with expert testimony he did not anticipate, on which he is unprepared or has no knowledge, and his own expert is absent, he has several possible courses:
(a) He can ask for a recess of the trial on the ground of surprise. If the recess is granted, he will have time to consult his own expert.
(b) If it is late in the day, he can examine the expert on other matters until time for adjournment and consult his expert before the trial resumes.
(c) If a recess is denied and adjournment time is far away he will have to confine the cross-examination to making the expert's opinion as definite as possible. Then he can either ask that the witness be excused, but preserve the right to recall him at a later date for further cross-examination, or refute the adverse opinion by the testimony of his own expert or by establishing that the facts on which the witness based his opinion were incorrect.
Opinion Based Solely on Experience
The expert witness today is cagey and usually refuses to state that he bases his opinion, even in part, on authoritative texts or treatises. (The witness cannot be cross-examined on texts or treatises that have not been admitted in evidence unless he states that he referred to, considered, or relied on them in arriving at or forming his opinion. Rather, he is inclined to state that his opinion is based solely on his experience. The cross-examination should then go into this experience.
Every now and then the lawyer is confronted with an expert who has only recently been admitted or licensed to practice his profession.
"Yes and No'' Answers
Many expert witnesses think it is clever to answer a question by stating "yes and no" and then explaining why the answer may be one or the other. In so doing, the witness either adds facts to or subtracts facts from the question as asked. The witness is not answering responsively, but is framing his own question and answering it. An attorney is entitled to have such an answer stricken from the record on motion, or to have the court instruct that the witness has not answered the question and that his answer must be disregarded. The attorney, whether on direct or on cross-examination, is entitled to a "yes" or a "no" on the exact facts contained in a fair question. He need not accept an answer on a set of facts distorted by the witness.
Use of Contrary Physical Evidence
The opinion of an expert witness is usually insufficient to overcome contrary facts sustained, corroborated, or established by admissible physical evidence presented for the inspection of the triers of fact. In other words, if the expert's opinion is contrary to a physical object in evidence, the opinion will ordinarily be given less weight than the physical evidence.
Use of Textbooks to Impeach Expert
An expert witness may not be impeached by cross- examining him about a text unless he "referred to, considered, or relied upon" that text in forming his opinion or the text has been admitted in evidence. Several decisions before enactment of the Evidence Code suggested that a cross-examiner could question the witness about any text on the same subject as those relied on by the witness.
Contradiction Does Not Always Impeach
Even when a witness bases his opinion in part on a designated text, the production of a contrary statement in the text does not always impeach him.
Refuting Opinion on Hypothetical Question
If on direct examination an expert is read a hypothetical question containing many facts and gives his opinion in reply, cross-examination calls for investigation of when the witness first heard of the problem and the research he may have done on it.
Note that, when asked for impeachment purposes, hypothetical questions need not be based on facts that are in evidence in the case.
