Which type of witness may be deposed solely to provide opinion testimony?

• A. Lay Witness
• B. Character Witness
• C. Rebuttal Witness
• D. Expert Witness

Answer: (D)

Specialized knowledge is what allows an expert to give opinions that go beyond what a layperson could determine from ordinary perception. An expert witness is brought in to analyze data, apply established methods, and draw conclusions in a way that helps the court understand complex issues. In a deposition, this means the expert can be asked to explain not only what they think, but also the data, methods, and reasoning behind their conclusions. That’s why this type of witness is used to provide opinion testimony.

Lay witnesses testify about things they directly observed or experienced, focusing on facts rather than expert analysis, even though they may express an opinion based on those perceptions—but that opinion is still grounded in ordinary experience. Character witnesses speak to reputation or character traits, not to specialized conclusions about technical or scientific questions. Rebuttal witnesses respond to specific evidence from the other side and can be either lay or expert, depending on what’s being challenged or supported. But when the goal is to obtain informed conclusions from specialized knowledge, the witness whose role is to provide those opinions is the expert.