Section 13.9 Opinions Based on Hypothetical Questions

• Library: Sources of Proof (2014 Ed.)

B. (§13.9) Opinions Based on Hypothetical Questions

With the enactment of § 490.065.4, RSMo 2000, use of the hypothetical question is no longer an absolute requirement. Section 490.065.4 states:

4. If a reasonable foundation is laid, an expert may testify in terms of opinion or inference and give the reasons therefor without the use of hypothetical questions, unless the court believes the use of a hypothetical question will make the expert’s opinion more understandable or of greater assistance to the jury due to the particular facts of the case.

This places the issue of whether a hypothetical question will be required within the discretion of the trial court. Before the statute, the hypothetical question was the traditional means to provide an expert with foundational facts for an opinion. The expert was asked to assume given facts and offer an opinion based on those facts. While the hypothetical is not required in every circumstance under current law, it is still permitted and may be required in the discretion of the court.

The hypothetical question does not need to include all material facts in evidence...