California Civil Jury Instructions (CACI) (2017)

221. Conflicting Expert Testimony

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221.Conflicting Expert Testimony
If the expert witnesses disagreed with one another, you should weigh
each opinion against the others. You should examine the reasons given
for each opinion and the facts or other matters that each witness relied
on. You may also compare the experts’ qualifications.
New September 2003
Directions for Use
Unless the issue is one that can be resolved only with expert testimony, the jury
should not be instructed that they must accept the entire testimony of the expert
whose testimony appears to be entitled to greater weight. (Santa Clara County
Flood Control and Water Conservation Dist. v. Freitas (1960) 177 Cal.App.2d 264,
268–269 [2 Cal.Rptr. 129].)
For an instruction on expert witnesses generally, see CACI No. 219, Expert
Witness Testimony. For an instruction on hypothetical questions, see CACI
No. 220, Experts—Questions Containing Assumed Facts.
Sources and Authority
• “[C]redibility of expert witnesses is a matter for the jury after proper
instructions from the court.” (Williams v. Volkswagenwerk Aktiengesellschaft
(1986) 180 Cal.App.3d 1244, 1265 [226 Cal.Rptr. 306].)
• “[W]e rely upon the rule of Sargon [Sargon Enterprises, Inc. v. University of
Southern California (2012) 55 Cal.4th 747 [149 Cal.Rptr.3d 614, 288 P.3d
1237]] that although trial courts ‘have a substantial “gatekeeping”
responsibility’ in evaluating proposed expert opinion, the gate tended is not a
partisan checkpoint.” (Davis v. Honeywell Internat. Inc. (2016) 245 Cal.App.4th
477, 492 [199 Cal.Rptr.3d 583], internal citation omitted.)
Secondary Sources
7 Witkin, California Procedure (5th ed. 2008) Trial, § 292
48 California Forms of Pleading and Practice, Ch. 551, Trial, § 551.70 (Matthew