While there is some professional debate about the usefulness of expert witness depositions in litigation practice, most practitioners I have encountered support the practice. Despite the expense associated with the deposition, which can include the reporter, travel, and the expert's fees (to say nothing of the attorneys' time), the benefits generally outweigh the cost. First, there is the opportunity to limit the scope of the expert's testimony by pinning her down. Second, there is the opportunity to identify the weaknesses in the expert's testimony, which can shorten considerably the time and scope of expert testimony at trial. Third, the deposition can form a basis to promote settlement before trial. Fourth, the deposition can form the basis of a motion for summary judgment. Fifth, the deposition provides a basis to challenge an expert on a motion in limine or under Daubert.
Because the cost and the utility of an expert deposition are high, every effort should be made to obtain the greatest possible yield from the experience. Despite this, shortcutting on preparation abounds. One tempting short-cut whose substantive use should be avoided is the use of "pattern" or "sample" questions. The ready availability of this resource is a trap for the unwary. The temptation to be under-prepared in a deposition heightens the risks.