The "Lay Opinion" Rule - Criminal Law

Witnesses must answer questions in the form of statements of what they saw, heard, felt, tasted, or smelled. Usually they are not permitted to express their opinions or draw conclusions. Under the FRE, a court will permit a person who is not testifying as an expert to testify in the form of an opinion if the opinion is both rationally based on his perception and helps to explain the witness's testimony. Additionally, a competent layperson may provide opinions on certain subjects that are specifically permitted by rule, statute, or case law. Some of these are:

Another person's identity
Another person's sanity
Demeanor, mood, or intent
Identification of handwriting
Intoxication or sobriety
Ownership
The state of health, sickness, or injury
Speed, distance, and size
The value of a witness's own property

Opinion testimony is not necessarily objectionable even if such testimony goes to the ultimate issue to be decided in the trial.

Extrinsic evidence is evidence other than the answers of the witness whose testimony is being impeached. It may be offered to prove facts relevant to impeaching a witness. In addition to extrinsic evidence, a party may attack the credibility of another witness by attempting to show that the witness is or has:

Bias, prejudice, interest in the issue, or corruption
Criminal convictions, or other prior bad acts
Prior inconsistent statements
An untruthful character

There are some limits to questioning a witness about a prior criminal conviction. However, according to the FRE, a witness may generally be questioned about criminal convictions when the crime was punishable by a sentence of more than a year or involved fraud or a false statement such as perjury. Before people attempt to use such evidence in a trial, they need to understand the limits to this kind of evidence.

The FRE allows questions about prior bad acts of a witness to impeach that witness's credibility where, in the court's discretion, the questions will help get at the truth. Thus, an attorney may ask questions about prior inconsistent statements if the following apply:

The questioner has a good faith basis for believing that the witness made an inconsistent statement
The witness needs to be reminded of the time, place, and circumstances of the prior statement
If the statement is written, a copy of the written statement must be provided to the opposing counsel upon request

Another way to impeach the testimony of a witness is to show that the witness has a character of untruthfulness. This departure from the basic rule states a party may not provide evidence of a witness's character to show that the witness acted in conformity with that character trait. The FRE permits evidence to prove a witness has a character of untruthfulness in:

Testimony of specific instances of untruthfulness
The opinion of another witness concerning the honesty of another witness's character
Testimony about the target witness's reputation for truthfulness in the community

It is important to know that a witness whose testimony is used to impeach the truthfulness of another witness may in turn be impeached