Legal Definitions - opinion rule

The opinion rule is a principle in evidence law that generally requires witnesses to testify about facts they personally observed, rather than offering their personal opinions, conclusions, or interpretations of those facts. The main goal of this rule is to ensure that the jury or judge, who are the "fact-finders" in a legal case, are the ones who draw conclusions and make inferences from the evidence presented, rather than relying on a witness's personal judgment.

Traditionally, this rule was applied quite strictly, aiming to keep all non-expert opinions out of court. The idea was that a witness should simply describe what they saw, heard, or did, and leave the "why" or "what it meant" to the jury.

However, modern courts recognize that it's not always possible or practical for witnesses to describe complex observations without some level of interpretation. Therefore, a non-expert witness's opinion may be allowed if it meets two conditions:

• It is rationally based on the witness's own perceptions – meaning it comes directly from what they personally experienced through their senses.
• It is helpful to clearly understand their testimony or to determine a fact – meaning it helps the jury understand the situation better than a mere recitation of raw facts would.

This allows for "shorthand" descriptions that are essentially factual observations expressed concisely (e.g., "the car was speeding" rather than listing exact speeds and distances, which might be impossible to recall precisely).

Here are some examples illustrating the opinion rule:

• Example 1 (Opinion Excluded - Speculation/Legal Conclusion):

  Imagine a witness testifying about a car accident they saw. If asked what happened, the witness states, "I think the driver of the red car was completely at fault because they were clearly distracted and driving recklessly."

  How it illustrates the rule: This statement would likely be excluded under the opinion rule. The witness is offering a legal conclusion ("at fault") and speculating about the driver's state of mind ("distracted," "recklessly"). Instead, the witness should testify to the facts they observed, such as "the red car swerved into the next lane without signaling" or "the driver of the red car was looking down at their phone just before the collision." It is then up to the jury to decide if those facts constitute fault or reckless driving.

• Example 2 (Opinion Allowed - Shorthand Description of Observation):

  Consider a witness describing a person's appearance or demeanor. The witness testifies, "The man who approached the counter looked very nervous; he was fidgeting with his hands and avoiding eye contact."

  How it illustrates the rule: While "nervous" is an opinion, it is rationally based on the witness's direct perceptions (fidgeting, avoiding eye contact) and is helpful for the jury to quickly understand the person's demeanor without requiring an exhaustive list of every subtle movement. It would be difficult for the witness to describe all the individual physical cues without using such a summary term, making this type of "shorthand" opinion generally admissible under the modern application of the rule.

• Example 3 (Opinion Excluded - Lack of Personal Perception or Expertise):

  Suppose a neighbor is testifying after a house fire and states, "In my opinion, the fire started due to faulty electrical wiring in the attic."

  How it illustrates the rule: This statement would likely be excluded. Unless the neighbor is a qualified fire investigator or electrician who personally examined the wiring and fire scene, their opinion about the cause of the fire is not rationally based on their own perceptions in a way that is helpful or reliable for the court. Determining the origin and cause of a fire typically requires specialized knowledge and investigation beyond what a layperson can offer. The neighbor could testify to what they saw (e.g., "I saw smoke coming from the attic window," "I heard a popping sound before the fire started"), but not offer an expert conclusion.