Legal Definitions - opinion testimony

Definition: Opinion testimony is evidence given by a witness based on their belief or idea rather than on direct knowledge of the facts at issue.

For example, a witness may testify that they believe a defendant is guilty based on their personal opinion, rather than on any direct evidence they have seen or heard. This type of testimony is allowed under certain conditions, and can come from either a lay witness or an expert witness.

Opinion testimony can be contrasted with affirmative testimony, which is testimony about whether something occurred or did not occur, based on what the witness saw or heard at the time and place in question. It can also be contrasted with negative testimony, which is testimony that something did not happen.

Overall, opinion testimony is important in legal proceedings because it can help to provide context and interpretation of the facts at issue, but it must be carefully evaluated to ensure that it is based on a rational understanding of the evidence.