California Civil Jury Instructions (CACI) (2017)

107. Witnesses

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A witness is a person who has knowledge related to this case. You will
have to decide whether you believe each witness and how important
each witness’s testimony is to the case. You may believe all, part, or
none of a witness’s testimony.
In deciding whether to believe a witness’s testimony, you may consider,
among other factors, the following:
(a) How well did the witness see, hear, or otherwise sense what he
or she described in court?
(b) How well did the witness remember and describe what
(c) How did the witness look, act, and speak while testifying?
(d) Did the witness have any reason to say something that was not
true? For example, did the witness show any bias or prejudice or
have a personal relationship with any of the parties involved in
the case or have a personal stake in how this case is decided?
(e) What was the witness’s attitude toward this case or about giving
Sometimes a witness may say something that is not consistent with
something else he or she said. Sometimes different witnesses will give
different versions of what happened. People often forget things or make
mistakes in what they remember. Also, two people may see the same
event but remember it differently. You may consider these differences,
but do not decide that testimony is untrue just because it differs from
other testimony.
However, if you decide that a witness did not tell the truth about
something important, you may choose not to believe anything that
witness said. On the other hand, if you think the witness did not tell the
truth about some things but told the truth about others, you may accept
the part you think is true and ignore the rest.
Do not make any decision simply because there were more witnesses on
one side than on the other. If you believe it is true, the testimony of a
single witness is enough to prove a fact.
New September 2003; Revised April 2004, June 2005, April 2007, December 2012,
June 2015, December 2016
Directions for Use
This instruction may be given as an introductory instruction or as a concluding
instruction after trial. (See CACI No. 5003, Witnesses.)
Sources and Authority
• Role of Jury. Evidence Code section 312.
Considerations for Evaluating the Credibility of Witnesses. Evidence Code
section 780.
• Direct Evidence of Single Witness Sufficient. Evidence Code section 411.
• “It should certainly not be of importance to tell the ordinary man of the world
that he should distrust the statements of a witness whom he believes to be a
liar.” (Wallace v. Pacific Electric Ry. Co. (1930) 105 Cal.App. 664, 671 [288 P.
Secondary Sources
7 Witkin, California Procedure (5th ed. 2008) Trial, § 281
1A California Trial Guide, Unit 22, Rules Affecting Admissibility of Evidence,
§ 22.30 (Matthew Bender)
48 California Forms of Pleading and Practice, Ch. 551, Trial, § 551.122 (Matthew