Can expert witnesses testify beyond their disclosed opinions at trial? Arreguin-Leon v. Hadco Construction Explained

In Arreguin-Leon v. Hadco Construction, the Utah Court of Appeals addressed a critical issue in expert witness discovery: whether experts can testify beyond their disclosed opinions when the opposing party elects deposition over a written report.

Background and Facts

Noe Arreguin-Leon was working on a ladder installing road signs along I-15 when a sleeping driver crashed into the construction site, knocking him from the ladder and causing serious injuries. Arreguin-Leon sued Hadco Construction, the general contractor, claiming it negligently failed to implement a proper traffic control plan. Plaintiff disclosed a traffic engineer as an expert witness to testify about five specific traffic control violations. During the expert’s deposition, Hadco’s counsel asked if he had any other opinions, and the expert answered “No.” However, at trial, the expert provided extensive causation testimony that had never been disclosed.

Key Legal Issues

The central issue was whether Rule 26 of the Utah Rules of Civil Procedure permits expert witnesses to testify beyond their disclosed opinions when the opposing party elects to depose the expert rather than obtain a written report. Hadco objected to the surprise causation testimony, arguing it violated disclosure requirements.

Court’s Analysis and Holding

The court rejected the plaintiff’s argument that electing deposition over a written report eliminates limitations on expert testimony scope. The court held that while written reports expressly limit testimony under Rule 26(a)(4)(B), depositions create similar limitations when the expert’s opinions are “locked in” through questioning. The court explained that experts remain bound by their deposition testimony and parties must supplement discovery responses, including deposition answers, under Rule 26(d)(4). Since the expert stated he had no other opinions during deposition but later provided causation testimony at trial, this constituted an undisclosed opinion requiring exclusion absent good cause or harmlessness.

Practice Implications

This decision reinforces the importance of thorough expert discovery regardless of whether you elect deposition or written report. Practitioners should ask comprehensive questions during expert depositions to lock in the scope of testimony and prevent surprise opinions at trial. The court emphasized that Rule 26’s goal is preventing “surprise” testimony, and this protection applies equally to depositions and reports. When experts exceed their disclosed opinions, the presumed remedy is exclusion of testimony unless the violation is harmless or justified by good cause.