General James “Mad Dog” Mattis famously told his troops, “Be polite and be professional, but have a plan to kill everybody you meet.” Attorneys cross-examining experts would be well advised to adopt that same mindset. Experts are in almost all cases, raising their hands and swearing to tell their version of the truth. An expert is the most dangerous type of witness because an expert has the power to opine about outcome-determinative issues that jurors are asked to decide. It follows that the cross-examination of an expert can make or break a case.

Important new amendments to the Texas Rules of Civil Procedure, effective in cases filed on or after Jan. 1 will change how trial lawyers cross-examine expert witnesses in state court cases in Texas. What has changed, and what remains the same in the wake of the amendments?