In present-day trials the use of expert opinion as evidence is more and more common and important. The trial lawyer must be adequately prepared to examine adverse expert witnesses. This means following certain procedures and undertaking some special preparations pertaining only to expert evidence.
Lawyer's Knowledge of Subject
Importance:
Counsel must have some knowledge of the potential subjects of expert opinion evidence in his case. Without it he cannot properly present his own expert witnesses, much less cross-examine the opposing experts. If the attorney is representing the plaintiff, he generally knows what subjects will be covered by expert witnesses, but when he represents the defendant, he must try to ascertain the subjects.
How to Acquire Sufficient Knowledge
Updating Past Information:
If the lawyer has formerly handled a case dealing with the same technical or scientific question, he will have some background of the subject, but he must be careful not to rely merely on his memory or past knowledge. Scientific research and knowledge are constantly advancing. Counsel can look over his old notes, but should also procure an up-to-date text or article on the subject. The expert can also advise counsel about or furnish him with texts or articles that support his contentions and refute those of the opposition.
The attorney can gather information by discussing the problem with his own expert witness. He must make a full disclosure of all the facts to the expert, withholding nothing. The expert, not the lawyer, knows what is or is not important and is the person most qualified to evaluate the technical aspects of the situation. He should be informed of the problem, told each party's contentions, and shown all reports, hospital or other records, and prior statements and depositions of opposing expert witnesses.
Elicit His Written Opinion:
It is best to have the expert give his opinion on the question in writing. The lawyer should not trust either the expert's memory or his own. The expert can also be of great value in preparing questions for counsel to ask, both on direct examination (of the expert himself) and on cross-examination of opposition experts. Counsel should not rely on his own ability or memory to phrase a question correctly on a specialized subject. An improperly phrased question may fail to produce the answer sought, or not allow a favorable witness to give the precise opinion he wishes to present. For example, a lawyer handling a case concerning a scientific matter stopped an expert on the street and asked his opinion on a statement of facts. The expert gave an opinion coinciding with the lawyer's contention. The expert was later called as a witness, without any other preparation, and failed to give the same opinion on the stand. After court, the lawyer asked why the expert had not given the expected testimony. The expert answered, "You never asked me a question that would permit me to give an answer containing the opinion you wished to develop."
Preparing Questions
If possible, counsel should procure copies of any documents pertaining to the case. For example, in a case dealing with personal injury or the mental condition of one of the parties, doctor's reports and hospital charts should be sought. Opinions or statements of the experts counsel believes will be called can be copied. After the lawyer has brought his knowledge up to date and consulted his own expert or experts, he should take statements or depositions of all opposition witnesses.
Summary of Prior Testimony
Summaries of any prior testimony by expert witnesses should be prepared. The following sample form sets forth one part of a summary of prior adverse testimony given by a doctor in a murder trial involving death from fractures of the skull.
List of Questions
Sufficient preparation includes drawing up a list of questions to ask the witness on cross-examination, together with any answers or statements previously given that are favorable to counsel's side or that contradict the witness's present testimony.
Examples of Successful Attacks
In a prosecution for homicide, the question was whether the victim committed suicide or whether his wife had shot him. He had died as the result of two revolver bullet wounds in his temple. At the first trial, the prosecutor attempted to establish that either bullet would have produced instantaneous unconsciousness and thus eliminate the proposition that the victim could have fired the second shot. He called as a witness an expert on ballistics, who correctly gave the formula for deter mining the striking force of a bullet (major premise) and then gave the elements of the formula for the bullets fired from the revolver-the amount of powder, weight of the bullet, distance traveled, etc. (minor premise). From these, he stated that the striking force of the bullet was about 900 pounds, enough to produce instantaneous unconsciousness (conclusion).
The jury could not agree on a verdict and the case was retried. Before the second trial, the prosecutor went over the expert's prior testimony, and the expert assured him that the testimony and calculations were absolutely correct. At the second trial, the expert gave the same testimony. On cross-examination the expert was asked where he had procured the figures for the amount of the charge, the weight of the bullet, etc. He replied that he had procured them from a table furnished by the arms company that manufactured the bullets. The table was produced, and it was shown that the expert had used figures not for the revolver bullets that were actually fired, but for rifle bullets of an entirely different size. The expert's testimony and the prosecutor s contention were given little if any weight by the jury. Another example occurred in an action on a life insurance policy. The plaintiff claimed that she was entitled to double indemnity because the insured died accidentally by unintentionally taking an overdose of Nembutal. The insurance company contended the man died a suicide. The insured had been suffering from an incurable disease. The day before his death he had procured 50 Nembutal capsules from the druggist, and the next morning only 20 capsules were left in the bottle. The autopsy showed death resulted from Nembutal poisoning. The plaintiff called an eminent doctor who testified that an overdose of Nembutal could produce death, that the deceased had taken 30 capsules as a result of "automatism," and that he thus died unintentionally. The doc tor described "automatism" as a result of forgetfulness: When a person is in the habit of doing a certain thing, such as taking one or two pills at a certain time, he can forget that he has already done it and do it once more automatically time and time again. This testimony, standing alone, was most impressive and could account for the insured's unintentional death. On cross-examination, however, it was developed that the man could not have taken 30 Nembutal capsules while operating under "automatism" because after taking about 6 capsules he would have lost consciousness.
Attacking Witness' Qualification as an Expert
If the lawyer discovers the names of experts to be called by his adversary, he can consult directories giving the background of persons in that field of expertise. This information may provide a basis for attacking the qualification of a witness as an expert.
