Witnesses must answer questions in the form of statements of what they saw, heard, felt, tasted, or smelled. Usually they're not permitted to express their opinions or draw conclusions. Under the Federal Rules of Evidence (FRE), a court will permit a person who isn't testifying as an expert to testify in the form of an opinion if it's both rationally based on their perception and helps to explain the witness's testimony. This is referred to as the "lay opinion" rule.
The following provides a brief introduction to the lay opinion rule, including the type of testimony that may be provided and the use of certain facts and opinions to impeach another witness.
When the Lay Opinion Rule Applies
In addition to opinions provided by an expert, a competent layperson may provide opinions on certain subjects that are specifically permitted by rule, statute, or case law. These subjects include but aren't limited to the following:
Opinion testimony is not necessarily objectionable even if such testimony goes to the ultimate issue to be decided in the trial.
Using Extrinsic Evidence to Impeach a Witness
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:
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 one 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.
Prior Bad Acts
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:
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:
It's important to know that a witness whose testimony is used to impeach the truthfulness of another witness may in turn be impeached.
Need Help Understanding the Laws of Evidence? An Attorney Can Help
The laws of evidence are rooted in the laws of the past. While these laws have grown and changed to meet the needs and mores of modern times, they still aren't always easy to comprehend. If you have questions about lay opinion or any other evidentiary question, get your inquires answered by a legal expert. Get started today and contact a local criminal defense lawyer.