Five Tips for Deposing an Expert Witness in Patent Litigation

With preparation and planning, an effective expert deposition can turn the tide in a patent case. A prepared deposing attorney can draw out inconsistencies in an expert’s opinion, identify deficiencies in the expert’s qualifications, and even get the expert to agree with highly damaging key facts. Armed with the proper information, a party can often exclude some or all of the expert’s testimony, successfully move for summary judgment on the basis of the expert’s damaging testimony, or lock the expert into damning testimony at trial.

The authors provide tips, along with Q & A examples of methods for deposing experts. Deposition testimony is most useful, they suggest, if the questions elicit short, pointed answers. Long, rambling answers with caveats and explanations, or testimony that requires reference back to previous questions and answers, is of little use.

Opposing experts, they note, will be well prepared to answer important questions in a very narrow context, but may be unprepared to answer essentially the same question asked a different way. An expert witness will often make broad conclusions based on only partial information or after having only analyzed part of an issue. When you dig a little deeper the expert may admit that such opinions are not based on any actual evidence, but on supposition.

A good strategy when deposing such an expert is to call out these instances and establish that the expert’s conclusion is based on unproven assumptions or incomplete facts.