1. Evidence law divides opinions into 3 categories:
a) Lay witness opinions
b) Opinions by skilled lay witnesses (usually police officers)
c) Expert opinions
2. The "opinion rule" expressed in Rule 701 concerns only with the first 2 categories of opinions and is a simple rule.
3. Expert opinions are covered by Rules 702-706. These are complicated rules which we will cover later in the course.
4. An opinion is characterized as an ordinary lay witness opinion if it is the kind of opinion expressed by people generally based on common experience, e.g., that the defendant was "drunk" and "driving around 90 miles per hour."
5. An opinion is characterized as a "skilled" lay opinion if it is the kind of opinion expressed by people with special experience. The subject matter is a common one (as opposed to something only a few people do, like brain surgery) but not a matter of universal experience, e.g., that a powder was "cocaine" (many people have never seen cocaine) or that graffiti spray painted on a wall were "gang symbols" (many people do not know what constitute gang symbols).
6. The opinion rule is that opinions are admissible if four criteria are met:
a) The witness has personal knowledge of the event and observed the thing that is the subject of the opinion,
b) The witness has the necessary experience to enable him or her to form reliable opinions about the subject. Common experience can be presumed, but
specialized experience must be proved.
c) The opinion is rationally based on the witness's observations
d) Presenting the testimony in opinion form will be helpful to the jury's understanding of the facts.
7. Because Rule 701 is a rule of admissibility, you cannot object simply because the witness is stating an opinion. You must argue that one or more of the four
criteria is not present. For example:
a) A 7-year-old child testifies that the defendant's car was going 60 miles an hour. You could object that the child lacks the necessary experience to make the
opinion reliable because the child does not drive a car.
b) A witness testifies she was 3 blocks away on a dark night and caught a glimpse of the defendant and he looked drunk. You could object that the opinion is
not rational because a typical person could not discern intoxication under those circumstances.
8. The "helpfulness" criterion is tricky. It does not mean relevant, i.e., will help the jury resolve disputes. It means that presenting the witness's observations in
opinion form is more helpful than asking the witness to give the underlying details. For example, the judge may have to decide which of the following two
methods of testifying is more helpful:
a) The defendant was drunk
b) The defendant left the bar at 2:00 a.m., staggered, stumbled, weaved back and forth, almost fell down twice, was loudly singing an Irish song off-key and
was slurring his words.
9. The "collective facts doctrine" (short-hand renditions) holds that an opinion is more helpful than a detailed factual description when the opinion reflects the
way people communicate about ordinary things. For example:
a) Conclusory testimony: He put salt on his french fries
b) Detailed testimony: He picked up a cream-colored cylinder about 3 inches tall with vertical ridges, inverted it, shook it up and down several times, and
some white crystals about 20 cubic microns came out and fell downward in the direction of a pile of yellowish-brown oblong hexahedrons.
10. The "waste of time" principle of Rule 403 holds that if an issue is unimportant or of little probative value, it is more helpful to summarize it quickly than
spend a lot of time on it. The admissibility of the opinion depends on what the contested issues are. For example:
a) If the defendant is on trial for bank robbery, it is more helpful to have the witnesses testify that he appeared drunk than to have each eyewitness explain the
underlying details of his appearance.
b) The reverse is true if the defendant is charged with driving while intoxicated. It is not helpful to have the arresting officer merely give his opinion that the
defendant was drunk. The jury should hear the details -- that the defendant ran off the road several times, and when he got out of his car, he staggered, fell,
smelled of beer, had red eyes, laughed loudly, dropped his car keys several times, and then fell flat on his face and lay there giggling when asked to walk a
straight line heel-to-toe.
11. There are several rules of thumb for opinion testimony:
a) Opinions of physical condition are admissible, but opinions of mental condition are not.
b) Opinions about the future are not admissible (speculation).
c) Opinions of speed, distance, time, and other measurements are admissible.
d) Opinions of the value of one's own property are admissible.
12. Lay witness may not testify to legal opinions, e.g., that they think the defendant is guilty.