People v. Anderson
495 N.E.2d 485, 113 Ill. 2d 1, 99 Ill. Dec. 104 (1986)
Premium Feature
Subscribe to Lexplug to listen to the Case Podcast.
Rule of Law:
An expert witness may testify about the underlying facts and data from otherwise inadmissible sources upon which they relied in forming their opinion, not for the truth of those matters, but for the limited purpose of explaining the basis of their opinion to the jury.
Facts:
- Clifford Anderson was employed as a janitor in the apartment building where he lived.
- For months, Anderson grew increasingly concerned that the building was being converted to condominiums and had his roommate write hundreds of letters to various agencies to complain.
- On September 2, 1978, Anderson was fired from his job.
- On the morning of September 5, 1978, Anderson's roommate observed him appearing not to have slept and described his behavior as 'wild'.
- After making several phone calls, Anderson seized a gun and shot and killed the building's manager and engineer.
- At trial, Anderson raised an insanity defense, and his psychiatric expert sought to testify about the contents of reports and statements from Anderson upon which he based his opinion.
Procedural Posture:
- Clifford Anderson was indicted on two counts of murder and two counts of armed violence in the circuit court of Cook County (trial court).
- Anderson's first trial ended in a mistrial when the jury could not reach a verdict.
- In a second trial, a jury found Anderson guilty on all counts.
- Following a bifurcated sentencing hearing, the jury sentenced Anderson to death.
- Anderson filed a direct appeal to the Supreme Court of Illinois (highest court).
Premium Content
Subscribe to Lexplug to view the complete brief
You're viewing a preview with Rule of Law, Facts, and Procedural Posture
Issue:
Does Illinois evidence law, following Federal Rules of Evidence 703 and 705, permit a psychiatric expert witness to disclose to the jury the otherwise inadmissible facts and data that form the basis of their opinion on a defendant's sanity?
Opinions:
Majority - Justice Simon
Yes. An expert witness may disclose the otherwise inadmissible facts and data upon which their opinion is based for the limited purpose of explaining their reasoning to the jury. The adoption of Federal Rules of Evidence 703 and 705 was intended to bring judicial practice in line with the real-world practice of experts. Because psychiatrists customarily rely on patient histories, other medical reports, and patient statements, they must be allowed to explain how this information informed their diagnosis. Depriving the jury of the reasons supporting an expert's opinion would render that opinion a 'meaningless conclusion' and prevent the jury from properly evaluating its weight and credibility. This underlying information is not considered hearsay because it is not offered to prove the truth of the matter asserted, but only to explain the basis of the opinion. A limiting instruction should be given to the jury to ensure they do not misuse the information as substantive evidence.
Analysis:
This decision significantly clarifies the scope of expert testimony in Illinois, aligning state practice with the federal rules and the majority of other jurisdictions. By allowing experts to reveal the underlying basis of their opinions, the court enhances the jury's ability to critically evaluate competing expert testimonies, especially in complex cases like those involving the insanity defense. This ruling moves away from the prior, more restrictive view on non-treating expert testimony and empowers the jury by providing a fuller context for expert conclusions. Consequently, trial practice will likely involve more detailed direct examinations of experts, focusing not just on their conclusions but on their entire diagnostic process.
