Presentation of evidence - Lay opinions

Learning Outcomes

After reading this article, you will be able to identify when lay opinion evidence is admissible in court, explain the requirements for lay witness opinion testimony, distinguish lay from expert opinion, and apply these principles to MBE-style questions. You will also recognize common exam traps and understand how to analyze fact patterns involving lay opinions.

MBE Syllabus

For MBE, you are required to understand the rules governing the admissibility of lay opinions and how they differ from expert opinions. This includes knowing the foundational requirements for lay opinion testimony and recognizing when such evidence is improper. In your revision, focus on:

  • The general rule excluding opinions and exceptions for lay opinions.
  • The three requirements for admissible lay opinion testimony.
  • The distinction between lay and expert opinion evidence.
  • The types of issues where lay opinion is commonly permitted.
  • The limits on the subject matter of lay opinion evidence.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

  1. Which of the following is NOT a requirement for admissible lay opinion testimony?
    1. The opinion is rationally based on the witness’s perception.
    2. The opinion is helpful to understanding the testimony or a fact in issue.
    3. The opinion is based on scientific, technical, or specialized knowledge.
    4. The opinion is not based on specialized knowledge.
  2. A witness testifies that a driver "looked drunk" after a car accident. Is this testimony generally admissible?
    1. Yes, if the witness observed the driver’s behavior.
    2. No, because only experts can give opinions on intoxication.
    3. Yes, but only if the witness is a police officer.
    4. No, because lay opinions are never admissible.
  3. In which situation is a lay opinion most likely to be inadmissible?
    1. Estimating the speed of a vehicle.
    2. Stating that someone appeared angry.
    3. Giving a medical diagnosis.
    4. Describing a person’s apparent age.

Introduction

Lay opinions are a frequent topic on the MBE. The general rule is that witnesses testify to facts, not opinions. However, courts allow lay witnesses to give opinions in limited circumstances. Understanding when a lay opinion is admissible—and when it is not—is essential for answering MBE questions correctly.

General Rule: No Opinions

The default rule is that witnesses must testify to facts they observed, not their opinions or conclusions. This ensures the jury or judge draws its own inferences from the facts.

Key Term: Lay Opinion
Testimony by a non-expert witness expressing an inference or conclusion based on the witness’s own perception, rather than specialized knowledge.

Exception: Admissible Lay Opinions

Courts allow lay opinions when strict factual testimony would be difficult or less helpful. The Federal Rules of Evidence (FRE 701) permit lay opinion testimony if three requirements are met:

  1. Rationally Based on Perception: The opinion must be grounded in the witness’s direct observations.
  2. Helpful to the Trier of Fact: The opinion must assist the jury or judge in understanding the witness’s testimony or determining a fact in issue.
  3. Not Based on Specialized Knowledge: The opinion must not require scientific, technical, or other specialized training (which would require qualification as an expert).

Key Term: Rationally Based on Perception
The opinion must arise from what the witness personally saw, heard, or otherwise sensed.

Key Term: Helpful to Trier of Fact
The opinion must clarify the witness’s testimony or make a fact in issue easier to understand.

Key Term: Not Based on Specialized Knowledge
The opinion must not rely on scientific, technical, or expert knowledge.

Common Subjects for Lay Opinions

Lay opinions are commonly allowed on:

  • The general appearance or condition of a person (e.g., "looked tired," "seemed intoxicated").
  • Emotional states (e.g., "appeared angry," "looked scared").
  • Speed, distance, or value estimates.
  • Identity of a person, handwriting, or voice (if based on familiarity).
  • Intoxication, if based on observed behavior.
  • Apparent age or health.

Prohibited Lay Opinions

Lay witnesses cannot give opinions that require specialized knowledge, such as:

  • Medical diagnoses.
  • Technical or scientific conclusions.
  • Legal conclusions (e.g., "He was negligent," "That was a valid contract").

Worked Example 1.1

A witness testifies, "The car was going very fast, maybe 60 miles per hour." The witness observed the car drive by but is not a mechanic or accident reconstructionist. Is this opinion admissible?

Answer: Yes. Estimating speed is a classic example of an admissible lay opinion, as long as it is based on the witness’s own perception and is helpful to the jury.

Worked Example 1.2

A bystander testifies, "The victim looked like he was having a heart attack." The bystander is not a doctor. Is this opinion admissible?

Answer: No. This is inadmissible because it requires medical training. The bystander may describe what was observed (e.g., "He clutched his chest and collapsed"), but cannot diagnose a medical condition.

Exam Warning

On the MBE, be careful not to confuse lay opinions with expert opinions. If the opinion requires scientific, technical, or specialized knowledge, the witness must be qualified as an expert. Lay witnesses cannot give such opinions, even if they have personal experience.

Revision Tip

If you see a question where a witness gives an opinion, ask: (1) Did the witness personally observe the events? (2) Is the opinion helpful? (3) Does it require expert knowledge? If the answer to (3) is yes, the testimony is inadmissible as a lay opinion.

Key Point Checklist

This article has covered the following key knowledge points:

  • Lay opinions are generally inadmissible unless three requirements are met: rational basis in perception, helpfulness, and no specialized knowledge.
  • Common admissible lay opinions include estimates of speed, appearance, emotions, and identity.
  • Lay opinions are inadmissible if they require expert or technical knowledge (e.g., medical or legal conclusions).
  • The distinction between lay and expert opinion is frequently tested on the MBE.

Key Terms and Concepts

  • Lay Opinion
  • Rationally Based on Perception
  • Helpful to Trier of Fact
  • Not Based on Specialized Knowledge
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