The subject matter may change from case to case. The discipline of preparing expert testimony does not.
Define the opinion precisely
Start by identifying every opinion the expert actually intends to offer and the degree of certainty attached to it. Separate the ultimate conclusion from the intermediate assumptions, calculations, observations, and facts used to reach it.
Understand the methodology
An expert’s field may be highly technical, but the examination still turns on a manageable set of questions: what method was used, why that method fits the question, what inputs were selected, what was excluded, and whether the method was applied consistently.
Master the record the expert used
Experts often rely on documents, measurements, histories, photographs, tests, data, literature, or other witnesses. The trial lawyer should know which parts of the record support the opinion, which undermine it, and which the expert never considered.
Identify assumptions and limits
Many strong examinations come from assumptions rather than abstract attacks on credentials. If an assumption changes, does the opinion change? What does the expert agree the opinion cannot establish? What alternative explanation remains possible?
Connect the expert to the trial theory
Technical testimony should not sit outside the rest of the case. On direct, the expert should advance a fact or inference the factfinder needs. On cross, the examination should narrow, undermine, or reposition the opinion in a way that supports the broader theory.
Make the science understandable
The advocate’s task includes translation. Exhibits, demonstratives, analogies, sequencing, and disciplined terminology can make complex testimony usable without distorting it.