The Illinois rules of evidence are the standards the state has set for admitting evidence in both criminal and civil proceedings. Evidence is anything that can be used as proof. In personal injury cases, that can include eyewitness testimony, expert witnesses, photographs, police reports, medical records and more.

The Illinois Rules of Evidence carry the following provisions:

• Relevancy and Its Limits (Article IV § § 401-413) — Evidence has to be relevant to an issue or matter of fact in the case. It is meant to demonstrate that an action is "more probable or less probable than it would be without the evidence."

  Evidence not directly related to the case is not allowed. Say you are filing a car accident injury claim against a drunk driver. You cannot admit evidence saying that 29 people die every day due to drunk driving. While relevant to drunk driving at large, it does not answer whether the driver you are making a claim against was drunk. A picture of the driver being arrested would be relevant.

  Under Ill. R. Evid. 403, evidence can also not be admitted if its relevance is outweighed by the danger of unfair prejudice or if it is deemed a waste of time.

• Privileges (Article V § § 501-502) — Evidence cannot be introduced if it was an inadvertent disclosure of communication usually covered under attorney-client privilege.
• Witnesses (Article VI § § 601-615) — The following rules were set forth about witness testimony:
  • They have to have personal knowledge of the matter (Ill. R. Evid. 602)
  • Before testifying, they make an oath declaring that they will testify truthfully (Ill. R. Evid. 603)
  • An interpreter must make an oath to "make a true translation" (Ill. R. Evid. 604)
  • Judges (Ill. R. Evid. 605) and members of the jury (Ill. R. Evid. 606) may not testify in a case they are presiding over or sitting in
  • The credibility of a witness may be attacked or supported through their reputation for truthfulness or untruthfulness (Ill. R. Evid. 608)
• Opinions and Expert Testimony (Article VII § § 701-705) — If someone who is not an expert witness is to be admitted to testify about their opinion, the opinions must be:
  • Rationally based on their perceptions
  • Helpful in determination of a fact at issue
  • Not based on scientific, technical or other specialized knowledge

  Someone who is called as an expert witness can only testify if:

  • They can assist the trier of fact in understanding evidence or determining a fact at issue
  • They are qualified through knowledge, skill, experience, training or education

  If they are testifying to an opinion they hold through "new or novel" scientific methodology, they must show how the methodology has gained general acceptance in the relevant field.

• Hearsay (Article VIII § § 801-806) — "Hearsay" is a statement a witness makes repeating the statement of another person, who made the statement out-of-court, when that statement cannot verified or corroborated. For example, you cannot say that a bartender told you someone was drunk unless the bartender is there themselves to testify. Hearsay is generally prohibited in testimony. Regardless of whether the person who made the statements is available to testify or not, there are exceptions for:
  • Excited utterances immediately after the incident in question ("I'm so sorry I hit you")
  • Statements made against interest (admissions or confessions)
  • Matters of record (contracts, employment information, etc...)
  • Statements made to receive medical treatment (describing symptoms or injuries to an emergency room doctor, for example)
  • Declarations about present state of mind ("I'm going to drink a lot tonight")
  • Inconsistent statements made by a witness, as long as the previous statement was signed

  If the person who made the original statement is unable to testify, there are exceptions for:

  • Dying declarations, or statements made under the belief of impending death
  • Former testimony, as long as the other party had an opportunity to cross-examine the person
  • Statement of personal or family history, as long as the person testifying was close enough to the person that the information is likely to be accurate
  • If the party the statement is being made against deliberately made the original declarant unavailable to testify
  • The original declarant testifies to lack of memory
• Contents of Writings, Recordings and Photographs (Article X § § 1001-1008) — Any writings, recordings or photographs admitted must be the originals. Exceptions apply if:
  • There is a legitimate question to the authenticity of the original
  • The originals were lost or destroyed
  • The originals cannot be legally obtained
  • The originals are in the possession of the other party
  • The writing, recording or photograph is not closely related to a controlling issue
  • The original is part of an official record

The Illinois Rules of Evidence apply to official trials and court proceedings. They do not apply to grand juries or preliminary hearings or examinations.