opinion evidence. opinion evidence fre 701-706 evid. code §§ 800-870

OPINION EVIDENCEOPINION EVIDENCE

OPINION EVIDENCEOPINION EVIDENCE

FRE 701-706FRE 701-706Evid. Code §§ 800-870Evid. Code §§ 800-870

Lay OpinionLay Opinion

FRE 701 – if not an expert, the witness’ FRE 701 – if not an expert, the witness’ testimony in the form of opinion or testimony in the form of opinion or inferences is limited.inferences is limited.

Must satisfy three conditions:Must satisfy three conditions: (a) rationally based on witness’ perception (a) rationally based on witness’ perception (b) helpful to clear understanding of testimony(b) helpful to clear understanding of testimony (c) not based on scientific, technical or other (c) not based on scientific, technical or other

specialized knowledge w/i scope of Rule 702specialized knowledge w/i scope of Rule 702

Lay Opinion (cont.)Lay Opinion (cont.)

Evid. Code § 800 - if not an expert, the Evid. Code § 800 - if not an expert, the witness’ testimony in the form of opinion is witness’ testimony in the form of opinion is limited as permitted by law, including but limited as permitted by law, including but not limited to an opinion that is:not limited to an opinion that is: (a) rationally based on witness’ perception (a) rationally based on witness’ perception (b) helpful to clear understanding of testimony(b) helpful to clear understanding of testimony


Evid. Code § 802 – a witness may testify Evid. Code § 802 – a witness may testify on direct examination to the reasons and on direct examination to the reasons and basis of opinionbasis of opinionThe trial court has the discretion to require The trial court has the discretion to require

foundation for the opinion to be established foundation for the opinion to be established before the opinion is givenbefore the opinion is given


Evid. Code § 870 – opinion as to sanity – Evid. Code § 870 – opinion as to sanity – a witness may state opinion as to the a witness may state opinion as to the sanity of a person when:sanity of a person when: (a) an intimate acquaintance (a) an intimate acquaintance (b) a subscribing witness to a writing, the (b) a subscribing witness to a writing, the

validity of which is in dispute, signed by validity of which is in dispute, signed by person whose sanity is in question, on issue person whose sanity is in question, on issue of sanity at time of signingof sanity at time of signing

(c) qualified under §§ 800 or 801 to testify to (c) qualified under §§ 800 or 801 to testify to opinionopinion

Lay Opinion (cont.)Lay Opinion (cont.) Examples of proper lay opinion:Examples of proper lay opinion:

Estimates: quantity, weight, height, value, time, Estimates: quantity, weight, height, value, time, distance, measure, velocitydistance, measure, velocity

Emotions: anger, joy, fear, excitement, love, hatred, Emotions: anger, joy, fear, excitement, love, hatred, sorrowsorrow

Character traits: truthfulness, mendacity, violence, Character traits: truthfulness, mendacity, violence, peacefulness, goodnesspeacefulness, goodness

Appearance: age, gender, build, manner of walking, Appearance: age, gender, build, manner of walking, type of hairtype of hair

Physical/mental condition: healthy, sick, intoxicated, Physical/mental condition: healthy, sick, intoxicated, irrational, insane, intelligent, developmentally disabled irrational, insane, intelligent, developmentally disabled

Objects: type of car, color, taste of food/drink, smellObjects: type of car, color, taste of food/drink, smell Conditions: whether, light, darkness, visibility, smellConditions: whether, light, darkness, visibility, smell

Expert OpinionExpert Opinion

FRE 702 FRE 702 Applies to scientific, technical or other Applies to scientific, technical or other

specialized knowledgespecialized knowledgeMust assist the trier of factMust assist the trier of fact

In understanding the evidenceIn understanding the evidence In determining a fact in issueIn determining a fact in issue


FRE 702FRE 702Must be an expert by reason of Must be an expert by reason of

knowledge, skill, experience, training or knowledge, skill, experience, training or educationeducation


FRE 702FRE 702May testify to opinion or otherwise, ifMay testify to opinion or otherwise, if

1) the testimony is based on sufficient facts or 1) the testimony is based on sufficient facts or data;data;

2) the testimony is the product of reliable 2) the testimony is the product of reliable principles or methods;principles or methods;

3) the witness has applied the principles and 3) the witness has applied the principles and methods reliably to the facts of the casemethods reliably to the facts of the case


FRE 703FRE 703The facts or data in the case on which the The facts or data in the case on which the

expert bases an opinion or inference may expert bases an opinion or inference may be perceived or known at or before the be perceived or known at or before the hearinghearing


FRE 703FRE 703 If of a type reasonably relied on by experts If of a type reasonably relied on by experts

in the field in forming opinions or in the field in forming opinions or inferences, the data or facts relied on need inferences, the data or facts relied on need not be admissible in evidence for the not be admissible in evidence for the opinion or inference to be admittedopinion or inference to be admitted


FRE 703FRE 703Facts or data that are otherwise Facts or data that are otherwise

inadmissible shall not be disclosed to the inadmissible shall not be disclosed to the jury by the proponent unless the court jury by the proponent unless the court determines that their probative value in determines that their probative value in assisting the jury to evaluate the expert’s assisting the jury to evaluate the expert’s opinion substantially outweighs their opinion substantially outweighs their prejudicial effectprejudicial effect


FRE 704 – opinion on ultimate issueFRE 704 – opinion on ultimate issue (a) subject to sub.(b), testimony in the form of an (a) subject to sub.(b), testimony in the form of an

opinion or inference otherwise admissible is not opinion or inference otherwise admissible is not objectionable because it embraces an ultimate objectionable because it embraces an ultimate issue to be decided by the trier of factissue to be decided by the trier of fact

(b) bar on testifying to whether or not a criminal (b) bar on testifying to whether or not a criminal defendant had required mental state where it is defendant had required mental state where it is an element of offensean element of offense

Accord Evid. Code § 805 and Penal Code §§ 25-Accord Evid. Code § 805 and Penal Code §§ 25-2929


FRE 705FRE 705The expert may give opinion without first The expert may give opinion without first

giving reasons for that opinion unless the giving reasons for that opinion unless the court requires otherwisecourt requires otherwise

The expert may always be required to The expert may always be required to disclose reasons and underlying facts and disclose reasons and underlying facts and data on cross-examinationdata on cross-examination

Accord Evid. Code § 802Accord Evid. Code § 802


FRE 706FRE 706The court may on its own motion appoint The court may on its own motion appoint

an independent expertan independent expertAccord Evid. Code § 730Accord Evid. Code § 730

Expert Opinion (cont.)Expert Opinion (cont.)

Evid. Code § 801 – if a witness is testifying Evid. Code § 801 – if a witness is testifying as an expert, opinion testimony is limited; as an expert, opinion testimony is limited; must be:must be: (a) related to a subject that is sufficiently (a) related to a subject that is sufficiently

beyond common experience that the expert beyond common experience that the expert opinion would assist the trier of fact; andopinion would assist the trier of fact; and

(b) based on a matter, …(b) based on a matter, …


Evid. Code § 801(b) – based on a matter, Evid. Code § 801(b) – based on a matter, …… Including the expert’s special knowledge, skill, Including the expert’s special knowledge, skill,

training and educationtraining and education


Evid. Code § 801(b) – based on a matter, Evid. Code § 801(b) – based on a matter, ……perceived by or personally known to the perceived by or personally known to the

witnesswitness


Evid. Code § 801(b) – based on a matter, Evid. Code § 801(b) – based on a matter, ……Or made known to the expert at or before the Or made known to the expert at or before the

hearinghearing


Evid. Code § 801(b) – based on a matter, Evid. Code § 801(b) – based on a matter, ……Whether or not admissibleWhether or not admissible


Evid. Code § 801(b) – based on a matter, Evid. Code § 801(b) – based on a matter, ……That is of the type that reasonably may be That is of the type that reasonably may be

relied on by an expert in forming an opinion relied on by an expert in forming an opinion on the subject to which the testimony relates,on the subject to which the testimony relates,


Evid. Code § 801(b) – based on a matter, Evid. Code § 801(b) – based on a matter, ……Unless an expert is precluded by law from Unless an expert is precluded by law from

using such matter as a basis for his opinionusing such matter as a basis for his opinion


Experts differ from lay witnesses in that Experts differ from lay witnesses in that they are allowed to testify and give they are allowed to testify and give opinions that may not be based on their opinions that may not be based on their personal observationspersonal observations


An expert can draw an inference in 3 An expert can draw an inference in 3 ways:ways:1) on the basis of evidence available to the 1) on the basis of evidence available to the

jury jury 2) hypothetical question based on evidence 2) hypothetical question based on evidence

admitted in caseadmitted in case3) provide an opinion based on reviewing the 3) provide an opinion based on reviewing the

type of information such an expert would type of information such an expert would reasonably rely onreasonably rely on


Note: allowing opinions based on the type of Note: allowing opinions based on the type of information such an expert in the field would rely information such an expert in the field would rely on conforms the evidentiary practice with the on conforms the evidentiary practice with the customs and practices of the experts customs and practices of the experts themselves.themselves. If sound medical practices allow doctors to reach If sound medical practices allow doctors to reach

important medical decisions on information provided important medical decisions on information provided by patients and specialists, such as radiologists, then by patients and specialists, such as radiologists, then those decisions should be sufficiently reliable to be those decisions should be sufficiently reliable to be used in court.used in court.


However, information customarily relied on However, information customarily relied on by an expert in the field does not mean by an expert in the field does not mean such information is admissible.such information is admissible.

Hearsay and best or secondary evidence Hearsay and best or secondary evidence rule objections may apply.rule objections may apply.

This concept is balanced against the idea This concept is balanced against the idea that the finder of fact may need to know that the finder of fact may need to know what that information is to determine the what that information is to determine the weight to give to the expert opinionweight to give to the expert opinion


Cross examining experts:Cross examining experts:

Same rules as apply to any witnessSame rules as apply to any witness

Additionally, may cross on data or facts relied on in Additionally, may cross on data or facts relied on in forming opinionforming opinion



May cross on data or facts NOT relied on in forming May cross on data or facts NOT relied on in forming opinion or UNAWARE ofopinion or UNAWARE of

Some limitations may apply depending on 1) whether Some limitations may apply depending on 1) whether data has been admitted into evidence; 2) whether data has been admitted into evidence; 2) whether expert referred to, considered or relied on material; 3) expert referred to, considered or relied on material; 3) whether the publication is established as reliable whether the publication is established as reliable authority by testimony of expert or another expert authority by testimony of expert or another expert testifying in casetestifying in case

FRE somewhat more generous to cross-examinerFRE somewhat more generous to cross-examiner



See People v. Doolin (2009) 45 Cal.4See People v. Doolin (2009) 45 Cal.4thth 390, 433-439 for 390, 433-439 for full discussion of cross of expert and rebuttal case.full discussion of cross of expert and rebuttal case.


Evid. Code § 810-824Evid. Code § 810-824Special rules of evidence applicable to Special rules of evidence applicable to

opinion evidence on ascertaining the value of opinion evidence on ascertaining the value of real propertyreal property

opinion evidence. opinion evidence fre 701-706 evid. code §§ 800-870

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