Prosecutors should anticipate that the defense will present
an expert witness, especially when the case requires medical, scientific, or
technical knowledge. Conducting the cross-examination of expert witnesses will
most likely be difficult since the counsels, the jury, and the judge do not
necessarily possess the technical knowledge to understand every detail of
expert testimony.
Today, David Serna discusses 3 ways and strategies
prosecutors can use to effectively go about the cross-examination of expert
witnesses.
1.
Know the common factual issues dealt with during
the examination of expert witnesses
This may vary per State. It is necessary to
know what issued may be raised. As a guide, Rule 702 of the Federal Rules on
Evidence allows expert testimony when these three issues are raised: 1) whether
the testimony is based on sufficient data or facts; 2) whether the testimony is
the product of reliable methods and principles; and 3) whether the witness has
applied the methods and principles reliably given the facts of the case.
David Serna says that prosecutors must
prepare and pay attention if any of these three issues has been raised in the
pleadings.
2.
Understand the topic or subject the expert
testimony will cover
Lack of technical knowledge is indeed a limitation
on the part of the prosecutor. To effectively ask questions during the
cross-examination of expert witnesses, it is necessary that the prosecutor acquaints
himself with basic knowledge on the subject matter.
That does not mean that he should read several
books on the topic. A good source would be the State’s own expert witness. This
should guide the prosecutor and trier of facts in understanding the
technicalities in the expert testimony of the opponent’s witness.
3.
Know the background of the expert witness
After gathering information on the subject,
the prosecutor must also know who the expert witness is. It is necessary to
know if such witness is experienced, skilled, and credible. So much can be
inferred from his employment history and educational background.
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