California Civil Jury Instructions (CACI) (2017)

219. Expert Witness Testimony

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219.Expert Witness Testimony
During the trial you heard testimony from expert witnesses. The law
allows an expert to state opinions about matters in his or her field of
expertise even if he or she has not witnessed any of the events involved
in the trial.
You do not have to accept an expert’s opinion. As with any other
witness, it is up to you to decide whether you believe the expert’s
testimony and choose to use it as a basis for your decision. You may
believe all, part, or none of an expert’s testimony. In deciding whether
to believe an expert’s testimony, you should consider:
a. The expert’s training and experience;
b. The facts the expert relied on; and
c. The reasons for the expert’s opinion.
New September 2003
Directions for Use
This instruction should not be given for expert witness testimony on the standard of
care in professional malpractice cases if the testimony is uncontradicted.
Uncontradicted testimony of an expert witness on the standard of care in a
professional malpractice case is conclusive. (Howard v. Owens Corning (1999) 72
Cal.App.4th 621, 632–633 [85 Cal.Rptr.2d 386]; Conservatorship of McKeown
(1994) 25 Cal.App.4th 502, 509 [30 Cal.Rptr.2d 542]; Lysick v. Walcom (1968) 258
Cal.App.2d 136, 156 [65 Cal.Rptr. 406].) In all other cases, the jury may reject
expert testimony, provided that the jury does not act arbitrarily. (McKeown, supra,
25 Cal.App.4th at p. 509.)
Do not use this instruction in eminent domain and inverse condemnation cases.
(See Aetna Life and Casualty Co. v. City of Los Angeles (1985) 170 Cal.App.3d
865, 877 [216 Cal.Rptr. 831]; CACI No. 3515, Valuation Testimony.)
For an instruction on hypothetical questions, see CACI No. 220,
Experts—Questions Containing Assumed Facts. For an instruction on conflicting
expert testimony, see CACI No. 221, Conflicting Expert Testimony.
Sources and Authority
• Qualification as Expert. Evidence Code section 720(a).
“Under Evidence Code section 720, subdivision (a), a person is qualified to
testify as an expert if he or she ‘has special knowledge, skill, experience,
training, or education sufficient to qualify him as an expert on the subject to
which his testimony relates. [T]he determinative issue in each case must be
whether the witness has sufficient skill or experience in the field so that his
testimony would be likely to assist the jury in the search for the truth . . . .
[Citation.] Where a witness has disclosed sufficient knowledge, the question of
the degree of knowledge goes more to the weight of the evidence than its
admissibility. [Citation.]’ ” (Lattimore v. Dickey (2015) 239 Cal.App.4th 959,
969 [191 Cal.Rptr.3d 766].)
• The “credibility 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].)
• “[U]nder Evidence Code sections 801, subdivision (b), and 802, the trial court
acts as a gatekeeper to exclude expert opinion testimony that is (1) based on
matter of a type on which an expert may not reasonably rely, (2) based on
reasons unsupported by the material on which the expert relies, or (3)
speculative. Other provisions of law, including decisional law, may also provide
reasons for excluding expert opinion testimony. [¶] But courts must also be
cautious in excluding expert testimony. The trial court’s gatekeeping role does
not involve choosing between competing expert opinions.” (Sargon Enterprises,
Inc. v. University of Southern California (2012) 55 Cal.4th 747, 771−772 [149
Cal.Rptr.3d 614, 288 P.3d 1237], footnote omitted.)
• “ ‘Generally, the opinion of an expert is admissible when it is “[r]elated to a
subject that is sufficiently beyond common experience that the opinion of an
expert would assist the trier of fact . . . .” [Citations.] Also, “[t]estimony in the
form of an opinion that is otherwise admissible is not objectionable because it
embraces the ultimate issue to be decided by the trier of fact.” [Citation.]
However, “ ‘Where the jury is just as competent as the expert to consider and
weigh the evidence and draw the necessary conclusions, then the need for
expert testimony evaporates.’ ” ’ Expert testimony will be excluded ‘ “ ‘when it
would add nothing at all to the jury’s common fund of information, i.e., when
‘the subject of inquiry is one of such common knowledge that men of ordinary
education could reach a conclusion as intelligently as the witness.” ’ ” ’ ”
(Burton v. Sanner (2012) 207 Cal.App.4th 12, 19 [142 Cal.Rptr.3d 782],
internal citations omitted.)
• Under Evidence Code section 801(a), expert witness testimony “must relate to a
subject that is sufficiently beyond common experience that the opinion of an
expert would assist the trier of fact.” (New v. Consolidated Rock Products Co.
(1985) 171 Cal.App.3d 681, 692 [217 Cal.Rptr. 522].)
• Expert witnesses are qualified by special knowledge to form opinions on facts
that they have not personally witnessed. (Manney v. Housing Authority of The
City of Richmond (1947) 79 Cal.App.2d 453, 460 [180 P.2d 69].)
• “Although a jury may not arbitrarily or unreasonably disregard the testimony of
an expert, it is not bound by the expert’s opinion. Instead, it must give to each
opinion the weight which it finds the opinion deserves. So long as it does not
do so arbitrarily, a jury may entirely reject the testimony of a plaintiff’s expert,
even where the defendant does not call any opposing expert and the expert
testimony is not contradicted.” (Howard, supra, 72 Cal.App.4th at p. 633,
citations omitted.)
Secondary Sources
1 Witkin, California Evidence (5th ed. 2012) Opinion Evidence, §§ 26–44
Jefferson, California Evidence Benchbook (3d ed. 1997) §§ 29.18–29.55
1 Levy et al., California Torts, Ch. 3, Proof of Negligence, § 3.04 (Matthew
3A California Trial Guide, Unit 60, Opinion Testimony, § 60.05 (Matthew Bender)
California Products Liability Actions, Ch. 4, The Role of the Expert, § 4.03
(Matthew Bender)
48 California Forms of Pleading and Practice, Ch. 551, Trial, §§ 551.70, 551.113
(Matthew Bender)