What Are the Illinois Rules of Evidence and Why Do They Matter?

Evidence is one of the most important aspects of any court case. During a trial, it paints as accurate a picture as possible of the events that brought people to the courtroom that day. Types of evidence can include physical objects, witness testimony, or video and audio recordings. What you may not know is that before evidence can be presented in court, it has to adhere to the rules of evidence, otherwise known as the laws of evidence, which encompass the legal principles regarding the proof of facts during a trial. There are both federal rules of evidence that are all-encompassing as well as ones that vary state-by-state. Here we’ll go over some of the most prominent Illinois rules of evidence.

What Are the Most Crucial Illinois Rules of Evidence?


In order to be presented in court, evidence must first be deemed relevant, otherwise it is deemed inadmissible. Relevant evidence is always tied directly to a case and cannot contain generalized information where extrapolation is needed. For instance, if someone is charged with a hit and run auto incident, a prosecutor cannot submit statistics on how often hit and runs occur. It may be interesting, it may be pertinent, but ultimately it is not evidence of wrongdoing on the defendant’s part.

Laying the Foundation 

“Laying the foundation” of evidence is a way of confirming that a piece of evidence is what it claims to be — one of the most crucial steps in the rules of evidence. Most pieces of evidence require a witness or expert testimony in order to verify its validity. But some pieces of evidence can lay their own foundation, such as newspapers and public records.


One of the most important rules of evidence is that hearsay is generally inadmissible. Hearsay is generally what it sounds like: rumors and gossip. Reliable evidence cannot be a second-hand reporting of another’s words or conversation. The nuance of language and the fallibility of human memory can easily misrepresent details or misinterpret intentions. Have you ever played the game telephone as a kid? If so, then you know that the more times information changes hands, the more likely it will be distorted. For this reason, it is much better to call to testify anybody who made a crucial statement as a witness during the trial.

For a statement to be considered hearsay, it must:

  • Initially be made outside of court
  • Be used in court by someone who did not make the statement; and 
  • Be used in court to prove what is said in the statement

Keep in mind, however, that there are exceptions to hearsay rules. Some are as follows:

  • Excited utterances: any statement made about a startling event, right after experiencing the event. For instance, somebody seeing a car crash and saying, “that red car ran right into that bus!”
  • Statements made to get medical treatment: if someone talks about their symptoms to receive medical treatment, their statements can likely be used in court because most people do not lie when they are talking to medical professionals to receive treatment. 
  • Statements made about mental or physical condition: statements made about your own mental and physical condition can also be permitted in some circumstances.

Character Evidence

Character evidence is any testimony or document that outlines someone’s personal disposition in order to measure the plausibility of that person acting a certain way. Character evidence, however, is most often not permissible. In order to be valid in a courtroom, there are three general factors that are considered:

  • Purpose: character evidence is usually only permissible in certain cases where it is crucial, such as in defamation lawsuits or child custody hearings. It can also be used to strengthen or discredit witness testimony or prove conduct through circumstantial evidence.
  • Form: character evidence can be offered in three main forms — expert opinions, reputation evidence, and as evidence of conduct in specific situations.
  • Type of Trial: the type of trial will largely dictate whether character evidence is admissible in court. For example, it is not admissible (generally) in criminal trials if a prosecutor presents it in order to outline the likelihood of a crime being committed. 

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If you or a loved one have been injured due to somebody else’s negligence, such as in an auto accident, due to medical malpractice,  or nursing home negligence, you may be entitled to significant compensation. Brian Lewis will help you and your family gain monetary justice and will help you through each step of the legal process. Schedule a free consultation today to get started.

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