What should an expert do if asked to rely on inadmissible facts or data?

• A. Explain the basis and limitations, seek admissible sources if possible, and disclose the reliance on inadmissible data while noting its status.
• B. Refuse to testify under any circumstance.
• C. Present all data as admissible.
• D. Ignore inadmissible data.

Answer: (A)

When an expert must rely on data that is not admissible, the key duty is transparency about the basis and limitations of the opinion, and to pursue admissible sources if possible. The expert should explain the data used to form the conclusion, clearly state that some of that data is inadmissible, and describe how that affects the strength or reliability of the opinion. If feasible, they should seek or supplement with admissible sources to support or refine the conclusion, while still disclosing any reliance on the inadmissible material. This approach preserves the integrity of the testimony and lets the court weigh the opinion with full awareness of what underpins it.

Other approaches fall short: refusing to testify at all isn’t warranted when the opinion can still be helpful with proper disclosure; presenting all data as admissible would misrepresent the evidence; and ignoring inadmissible data would misstate how the opinion was formed.