Legal matter expert witness

FRE 704 states (a) except as provided in subdivision (b), testimony in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact (c) no expert witness testifying with respect to the mental state or condition of a defendant in a criminal case may state an opinion or inference as to whether the defendant did or did not have the mental state or condition constituting an element of the crime charged or of a defense thereto. Such ultimate issues are matters for the trier of fact alone. (Importantly, ERE 704 does not permit expert witnesses to offer legal conclusions, or to directly express opinions about the credibility of other witnesses.)... 

But the "jury member" analogy fails to capture a vital component of evaluation the report is directed toward highly trained participants in laboratory research. Even if the reader never performed the experiment described in the report, the reader typically appeals to direct participation in experiments that are similar to those described. At least privately, the reader rehearses the kind of malfunctions of apparatus, mistakes of implementation, and interfering effects that plagued past experiments. Are such dangers relevant to the present experiment If so, are they avoidable The answers to these questions require a command of the subject matter that is usually reserved for expert witnesses. The metaphor of "reader as jury member" fails to capture such a requirement of the reader. In the context of the legal system in the United States, jury members are rarely trained in the topics examined by expert witnesses. So, because a virtual witness is usually well versed in the techniques of laboratory research, the... 

If the facts in a legal case involve specialized and technical subject areas, expert witnesses may testify in the case. A case may require the expertise of engineers, safety professionals and other specialists. For example, physicians usually testify about product injuries. In products liability cases, engineers often testify about a product, existence of defects, use of the product, design alternatives, negligence, compliance with published standards or standards of practice, the state of the art, and other matters. 

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