The information that you and your attorney present at trial matters in the eventual outcome of a case, but so does the way that information is presented. The rules of evidence matter during both the trial itself and during any appeals processes. Understanding how to manage and present evidence in keeping with the rules is essential, and seeing where the other party didn't do so can help you win an appeal.
Oregon's evidence rules cover physical evidence, notices and requirements, general witnesses and expert opinions and witnesses. For example, a witness can't testify in a case unless he or she is shown to have personal knowledge of whatever he or she will be testifying about. Expert witnesses have to qualify as such, meaning they must present with the right background, education, skills or training to be considered an expert on the matter.
Hearsay testimony isn't allowed to be admitted to an Oregon court, and the definition of hearsay is governed by two separate Oregon statutes. Writings and other documents might be admitted as evidence in a case, but many situations require that the original document is produced. Some exceptions are provided under Oregon law.
Understanding all the rules of evidence is almost impossible for someone who is not a legal professional. Keeping up with all the exceptions and when they might come into play is even more difficult. If you are in the middle of a civil case or you are planning to appeal a civil decision, then understanding such rules is critical to success. Working with a professional who is well-versed in Oregon law and appeals procedures can help you seek a successful outcome.
Source: Oregon Laws, "Chapter 40 Evidence Code," accessed Dec. 18, 2015