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Illinois Rules Of Evidence Expert Testimony Essay

(a)In General. To satisfy the requirement of authenticating or identifying an item of evidence, the proponent must produce evidence sufficient to support a finding that the item is what the proponent claims it is.

(b)Examples. The following are examples only — not a complete list — of evidence that satisfies the requirement:

(1)Testimony of a Witness with Knowledge. Testimony that an item is what it is claimed to be.

(2)Nonexpert Opinion About Handwriting. A nonexpert’s opinion that handwriting is genuine, based on a familiarity with it that was not acquired for the current litigation.

(3)Comparison by an Expert Witness or the Trier of Fact. A comparison with an authenticated specimen by an expert witness or the trier of fact.

(4)Distinctive Characteristics and the Like. The appearance, contents, substance, internal patterns, or other distinctive characteristics of the item, taken together with all the circumstances.

(5)Opinion About a Voice. An opinion identifying a person’s voice — whether heard firsthand or through mechanical or electronic transmission or recording — based on hearing the voice at any time under circumstances that connect it with the alleged speaker.

(6)Evidence About a Telephone Conversation. For a telephone conversation, evidence that a call was made to the number assigned at the time to:

(A) a particular person, if circumstances, including self-identification, show that the person answering was the one called; or

(B) a particular business, if the call was made to a business and the call related to business reasonably transacted over the telephone.

(7) Evidence About Public Records. Evidence that:

(A) a document was recorded or filed in a public office as authorized by law; or

(B) a purported public record or statement is from the office where items of this kind are kept.

(8) Evidence About Ancient Documents or Data Compilations. For a document or data compilation, evidence that it:

(A) is in a condition that creates no suspicion about its authenticity;

(B) was in a place where, if authentic, it would likely be; and

(C) is at least 20 years old when offered.

(9) Evidence About a Process or System. Evidence describing a process or system and showing that it produces an accurate result.

(10) Methods Provided by a Statute or Rule. Any method of authentication or identification allowed by a federal statute or a rule prescribed by the Supreme Court.


(Pub. L. 93–595, §1, Jan. 2, 1975, 88 Stat. 1943; Apr. 26, 2011, eff. Dec. 1, 2011.)

Notes of Advisory Committee on Proposed Rules

Subdivision (a). Authentication and identification represent a special aspect of relevancy. Michael and Adler, Real Proof, 5 Vand.L.Rev. 344, 362 (1952); McCormick §§179, 185; Morgan, Basic Problems of Evidence 378. (1962). Thus a telephone conversation may be irrelevant because on an unrelated topic or because the speaker is not identified. The latter aspect is the one here involved. Wigmore describes the need for authentication as “an inherent logical necessity.” 7 Wigmore §2129, p. 564.

This requirement of showing authenticity or identity fails in the category of relevancy dependent upon fulfillment of a condition of fact and is governed by the procedure set forth in Rule 104(b).

The common law approach to authentication of documents has been criticized as an “attitude of agnosticism,” McCormick, Cases on Evidence 388, n. 4 (3rd ed. 1956), as one which “departs sharply from men's customs in ordinary affairs,” and as presenting only a slight obstacle to the introduction of forgeries in comparison to the time and expense devoted to proving genuine writings which correctly show their origin on their face, McCormick §185, pp. 395, 396. Today, such available procedures as requests to admit and pretrial conference afford the means of eliminating much of the need for authentication or identification. Also, significant inroads upon the traditional insistence on authentication and identification have been made by accepting as at least prima facie genuine items of the kind treated in Rule 902, infra. However, the need for suitable methods of proof still remains, since criminal cases pose their own obstacles to the use of preliminary procedures, unforeseen contingencies may arise, and cases of genuine controversy will still occur.

Subdivision (b). The treatment of authentication and identification draws largely upon the experience embodied in the common law and in statutes to furnish illustrative applications of the general principle set forth in subdivision (a). The examples are not intended as an exclusive enumeration of allowable methods but are meant to guide and suggest, leaving room for growth and development in this area of the law.

The examples relate for the most part to documents, with some attention given to voice communications and computer print-outs. As Wigmore noted, no special rules have been developed for authenticating chattels. Wigmore, Code of Evidence §2086 (3rd ed. 1942).

It should be observed that compliance with requirements of authentication or identification by no means assures admission of an item into evidence, as other bars, hearsay for example, may remain.

Example (1). Example (1) contemplates a broad spectrum ranging from testimony of a witness who was present at the signing of a document to testimony establishing narcotics as taken from an accused and accounting for custody through the period until trial, including laboratory analysis. See California Evidence Code §1413, eyewitness to signing.

Example (2). Example (2) states conventional doctrine as to lay identification of handwriting, which recognizes that a sufficient familiarity with the handwriting of another person may be acquired by seeing him write, by exchanging correspondence, or by other means, to afford a basis for identifying it on subsequent occasions. McCormick §189. See also California Evidence Code §1416. Testimony based upon familiarity acquired for purposes of the litigation is reserved to the expert under the example which follows.

Example (3). The history of common law restrictions upon the technique of proving or disproving the genuineness of a disputed specimen of handwriting through comparison with a genuine specimen, by either the testimony of expert witnesses or direct viewing by the triers themselves, is detailed in 7 Wigmore §§1991–1994. In breaking away, the English Common Law Procedure Act of 1854, 17 and 18 Viet., c. 125, §27, cautiously allowed expert or trier to use exemplars “proved to the satisfaction of the judge to be genuine” for purposes of comparison. The language found its way into numerous statutes in this country, e.g., California Evidence Code §§1417, 1418. While explainable as a measure of prudence in the process of breaking with precedent in the handwriting situation, the reservation to the judge of the question of the genuineness of exemplars and the imposition of an unusually high standard of persuasion are at variance with the general treatment of relevancy which depends upon fulfillment of a condition of fact. Rule 104(b). No similar attitude is found in other comparison situations, e.g., ballistics comparison by jury, as in Evans v. Commonwealth, 230 Ky. 411, 19 S.W.2d 1091 (1929), or by experts, Annot. 26 A.L.R.2d 892, and no reason appears for its continued existence in handwriting cases. Consequently Example (3) sets no higher standard for handwriting specimens and treats all comparison situations alike, to be governed by Rule 104(b). This approach is consistent with 28 U.S.C. §1731: “The admitted or proved handwriting of any person shall be admissible, for purposes of comparison, to determine genuineness of other handwriting attributed to such person.”

Precedent supports the acceptance of visual comparison as sufficiently satisfying preliminary authentication requirements for admission in evidence. Brandon v. Collins, 267 F.2d 731 (2d Cir. 1959); Wausau Sulphate Fibre Co. v. Commissioner of Internal Revenue, 61 F.2d 879 (7th Cir. 1932); Desimone v. United States, 227 F.2d 864 (9th Cir. 1955).

Example (4). The characteristics of the offered item itself, considered in the light of circumstances, afford authentication techniques in great variety. Thus a document or telephone conversation may be shown to have emanated from a particular person by virtue of its disclosing knowledge of facts known peculiarly to him; Globe Automatic Sprinkler Co. v. Braniff, 89 Okl. 105, 214 P. 127 (1923); California Evidence Code §1421; similarly, a letter may be authenticated by content and circumstances indicating it was in reply to a duly authenticated one. McCormick §192; California Evidence Code §1420. Language patterns may indicate authenticity or its opposite. Magnuson v. State, 187 Wis. 122, 203 N.W. 749 (1925); Arens and Meadow, Psycholinguistics and the Confession Dilemma, 56 Colum.L.Rev. 19 (1956).

Example (5). Since aural voice identification is not a subject of expert testimony, the requisite familiarity may be acquired either before or after the particular speaking which is the subject of the identification, in this respect resembling visual identification of a person rather than identification of handwriting. Cf. Example (2), supra, People v. Nichols, 378 Ill. 487, 38 N.E.2d 766 (1942); McGuire v. State, 200 Md. 601, 92 A.2d 582 (1952); State v. McGee, 336 Mo. 1082, 83 S.W.2d 98 (1935).

Example (6). The cases are in agreement that a mere assertion of his identity by a person talking on the telephone is not sufficient evidence of the authenticity of the conversation and that additional evidence of his identity is required. The additional evidence need not fall in any set pattern. Thus the content of his statements or the reply technique, under Example (4), supra, or voice identification under Example (5), may furnish the necessary foundation. Outgoing calls made by the witness involve additional factors bearing upon authenticity. The calling of a number assigned by the telephone company reasonably supports the assumption that the listing is correct and that the number is the one reached. If the number is that of a place of business, the mass of authority allows an ensuing conversation if it relates to business reasonably transacted over the telephone, on the theory that the maintenance of the telephone connection is an invitation to do business without further identification. Matton v. Hoover Co., 350 Mo. 506, 166 S.W.2d 557 (1942); City of Pawhuska v. Crutchfield, 147 Okl. 4. 293 P. 1095 (1930); Zurich General Acc. & Liability Ins. Co. v. Baum, 159 Va. 404, 165 S.E. 518 (1932). Otherwise, some additional circumstance of identification of the speaker is required. The authorities divide on the question whether the self-identifying statement of the person answering suffices. Example (6) answers in the affirmative on the assumption that usual conduct respecting telephone calls furnish adequate assurances of regularity, bearing in mind that the entire matter is open to exploration before the trier of fact. In general, see McCormick §193; 7 Wigmore §2155; Annot., 71 A.L.R. 5, 105 id. 326.

Example (7). Public records are regularly authenticated by proof of custody, without more. McCormick §191; 7 Wigmore §§2158, 2159. The example extends the principle to include data stored in computers and similar methods, of which increasing use in the public records area may be expected. See California Evidence Code §§1532, 1600.

Example (8). The familiar ancient document rule of the common law is extended to include data stored electronically or by other similar means. Since the importance of appearance diminishes in this situation, the importance of custody or place where found increases correspondingly. This expansion is necessary in view of the widespread use of methods of storing data in forms other than conventional written records.

Any time period selected is bound to be arbitrary. The common law period of 30 years is here reduced to 20 years, with some shift of emphasis from the probable unavailability of witnesses to the unlikeliness of a still viable fraud after the lapse of time. The shorter period is specified in the English Evidence Act of 1938, 1 & 2 Geo. 6, c. 28, and in Oregon R.S. 1963, §41.360(34). See also the numerous statutes prescribing periods of less than 30 years in the case of recorded documents. 7 Wigmore §2143.

The application of Example (8) is not subject to any limitation to title documents or to any requirement that possession, in the case of a title document, has been consistent with the document. See McCormick §190.

Example (9). Example (9) is designed for situations in which the accuracy of a result is dependent upon a process or system which produces it. X-rays afford a familiar instance. Among more recent developments is the computer, as to which see Transport Indemnity Co. v. Seib, 178 Neb. 253, 132 N.W.2d 871 (1965); State v. Veres, 7 Ariz.App. 117, 436 P.2d 629 (1968); Merrick v. United States Rubber Co., 7 Ariz.App. 433, 440 P.2d 314 (1968); Freed, Computer Print-Outs as Evidence, 16 Am.Jur. Proof of Facts 273; Symposium, Law and Computers in the Mid-Sixties, ALI-ABA (1966); 37 Albany L.Rev. 61 (1967). Example (9) does not, of course, foreclose taking judicial notice of the accuracy of the process or system.

Example (10). The example makes clear that methods of authentication provided by Act of Congress and by the Rules of Civil and Criminal Procedure or by Bankruptcy Rules are not intended to be superseded. Illustrative are the provisions for authentication of official records in Civil Procedure Rule 44 and Criminal Procedure Rule 27, for authentication of records of proceedings by court reporters in 28 U.S.C. §753(b) and Civil Procedure Rule 80(c), and for authentication of depositions in Civil Procedure Rule 30(f).

Committee Notes on Rules—2011 Amendment

The language of Rule 901 has been amended as part of the restyling of the Evidence Rules to make them more easily understood and to make style and terminology consistent throughout the rules. These changes are intended to be stylistic only. There is no intent to change any result in any ruling on evidence admissibility.

An expert witness new foundational element is being implemented by an Illinois appellate court. This is their way of dealing with unreliable expert testimony. See Committee on Identifying the Needs of the Forensic Sciences Community, National Research Council 

Illinois courts are dealing with unreliable expert witness testimony by creating a new foundational element.

See People v. Jones, 2015 IL App (1st) 121016 (04/22/2015).

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What is This Case About?

The defendant was convicted in a jury trial of first-degree murder based on circumstantial evidence. It was a close case with no eyewitnesses to the shooting. Defendant denied being the shooter. However, a gun was recovered from his home.

A bullet fell out of the victim’s body and and casings were recovered from the crime scene. A forensic scientist from the Illinois State Police laboratory specializing in firearms identification testified as an expert witness.

The firearm/toolmark examiner testified that the question of what is “sufficient agreement” between the items is based on his training and experience. ¶  34. The expert testified that he does not use a national standard, and that examinations at the Illinois State Police laboratory are “just based on our training and experience, which is verified by another examiner,” and that there is no Illinois State Police standard. ¶ 34.

The expert gave his opinion that there was sufficient agreement between the bullet recovered from the victim’s body and the test bullets fired from defendant's gun. Thus, the bullet recovered from the victim’s body was fired from defendant's gun.


Was there a  sufficient foundation laid by the expert witness allowing him to establish a sufficient basis for the expert’s opinion testimony?

To begin to answer this question we must first look at the rules.

What Precisely Are the Rules on Admitting an Expert Witness?

Three Illinois Rules of Evidence are relevant here.

Let’s look at …

Rule 702 Testimony by Experts

If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise. Where an expert witness testifies to an opinion based on a new or novel scientific methodology or principle, the proponent of the opinion has the burden of showing the methodology or scientific principle on which the opinion is based is sufficiently established to have gained general acceptance in the particular field in which it belongs. Rule 702.

Rule 703 Bases of Opinion Testimony By Experts

The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence. Rule 703.

Rule 705 Disclosure of Facts or Data

The expert may testify in terms of opinion or inference and give reasons therefor without first testifying to the underlying facts or data, unless the court requires otherwise. The expert may in any event be required to disclose the underlying facts or data on cross-examination. Rule 705.

According to these rules, it is clear that a witness who has been qualified as an expert witness need not testify “to the underlying facts or data” on which the opinion is based upon. Rule 705. “The facts or data need not be admissible in evidence.” Rule 703.


However, the reviewing court in this case ruled that “all expert testimony, whether scientific or not, must have an adequate foundation in order to be admissible.” ¶ 54. “[T]he admission of an expert's testimony requires the proponent to lay an adequate foundation establishing that the information upon which the expert bases his opinion is reliable.” ¶ 54 quoting People v. Safford, 392 Ill. App. 3d 212, 221 (2009).

The court held that:

This foundational requirement is required for the admission of all expert opinions. ¶ 54.

The appellate court then proceeded to overturn the murder conviction because the the testifying expert failed to explain the specific striations that he used to form his opinion. Thus, this expert failed to lay an adequate foundation.

So, if prosecutors have to start making sure to elicit the exact data points from the expert before the expert gives her opinion then this a rule the judges are creating from the case law.

Where Does it Come From?

Well, the reviewing court cited People v. Safford, 392 Ill. App. 3d 212, 221 (2009) (quoting Hiscott v. Peters, 324 Ill. App. 3d 114, 122 (2001), citing Soto v. Gaytan, 313 Ill. App. 3d 137, 146 (2000)) when it described this foundational element.

The appellate court also felt that “[p]art of the general foundation requirement for expert testimony is that ‘it must be shown that the facts or data relied upon by the expert are of a type reasonably relied upon by [experts] in that particular field in forming opinions or inferences.” People v. Smith, 2012 IL App (1st) 102354, ¶ 70 (quoting People v. Contreras, 246 Ill. App. 3d 502, 510 (1993)).

The court saw this as an admissibility issue, not merely weight.

The court was acutely aware of the 2009 forensic science report that widely condemned many scientific procedures as being widely unreliable. See this report here.

Where It DID NOT Come From?

One thing is for sure. This “foundational” element for admission of an expert witness opinion is not in the rules.

As stated above, Rules 702, 703 and 705 do not require that the expert witness first explain what data is being relied upon to form the expert’s opinion. They rules say quite the opposite.


The case that is often cited as the case establishing Illinois as a “Frye” state is Donaldson v. Central Illinois Public Service Co., 199 Ill.2d 63, 767 N.E.2d 314 (2002). Rule 702 itself refers to this case in the comments.

Remember, a Frye Hearing is required whenever scientific evidence is new or novel. This was not the issue in this case.

During the initial “Are we a Frye State Debate?” the idea of “Frye-plus-reliability” first came up. This was the idea that after a scientific technique or methodology is recognized as generally accepted, a trial court should still have to consider whether the opinion in the case is reliable.

On this issue, in 2002, the Illinois Supreme Court held that

Today, we clarify that this is not the standard in Illinois. The trial court is not required to conduct a two-part inquiry into both the reliability of the methodology and its general acceptance. The determination of the reliability of an expert's methodology is naturally subsumed by the inquiry into its general acceptance in the scientific community. Simply put, a principle or technique is not generally accepted in the scientific community if it is by nature unreliable. Additionally, the Frye-plus-reliability test impermissibly examines the data from which the opinion flows, while the technique remains generally accepted. Questions concerning underlying data, and an expert's application of generally accepted techniques, go to the weight of the evidence, rather than its admissibility. Donaldson, 199 Ill.2d at 81.

The Illinois Supreme Court Has More Than Just Rules on This Issue

The closest the Illinois Supreme has come to a foundational element for expert witnesses was in People v. McKown, 236 Ill.2d 278 (2010).

This is the case where the Court held that the “admissibility of HGN evidence in an individual case will depend on the State’s ability to lay a proper foundation and to demonstrate the qualification of its witness, subject to the balancing of probative value with the risk of unfair prejudice.” [emphasis added] McKnown, 236 Ill.2d at 314.

The Illinois Supreme Court did not even come close to creating a foundational element for expert witnesses.

Instead the Court:

  • Tied he qualifications of the expert to how test is conducted
  • HGN only admissible if NHTSA protocol is followed
  • Only a properly trained officer could follow the protocol
  • Opinion can only show consumption of alcohol

See McKnown, 236 Ill.2d at 306.

The court specifically held ”that evidence of HGN field-sobriety testing, when performed according to the  NHTSA protocol by a properly trained officer, is admissible under the Frye test for the purpose of showing whether the subject has likely consumed alcohol and may be impaired.” 236 Ill.2d at 306.

The appellate court in the case at hand did not cite to McKnown for this principle.

Big Picture

The basic situation confronting the trial and appellate courts is this: They have to figure out what to do with scientific evidence that is not new nor novel yet for some reason deemed unreliable when applied to a specific case.

General Frye standards say the expert opinion is admissible if the expert is qualified. Under this rule, the defense is allowed to show jury the data points that  the expert used to form their opinion.

That is what the line about letting it go to the weight but not the admissibility is all about.

This invented approach creates a new foundational element that takes into account the reliability of the evidence before allowing it to ever be seen by the jury.

This sounds like a “Frye-Plus-Reliability” standard but of course the court is not calling it that.

What They Should Have Done

McKnown hints at what the correct procedural pathway the court should have followed. The Court stated its ruling was “subject to the balancing of probative value with the risk of unfair prejudice.” McKnown, 236 Ill.2d at 314.

We know what that is. Its the 403 balancing we do in practically every case! See Rule 403 Exclusion of Relevant Evidence on Grounds of Prejudice, Confusion, or Waste of Time.

I know I looks like I want to a whole lot of trouble to point out an “error” in a case that I believe had the right outcome.

But I think the rules the matter.

List of Cases

Filed Under: Evidence, Podcast