Commercial Litigation and Arbitration

A Simplified Approach to Computer-Generated Evidence and Animations

Gregory P. Joseph

It is not necessary to understand computers to be able to address the evidentiary issues that computer-generated evidence presents. Three principles simplify the process. First, there are certain common types of computer-generated evidence that present no genuine issues of trustworthiness. For these, ordinary evidence rules are sufficient to gauge admissibility without reference to the fact that the exhibits have in fact emanated from a computer. Second, some types of computer-generated exhibits are inherently hearsay because they reflect extrajudicial assertions. For those, it is necessary to consider whether any hearsay exception or exemption applies. Third, if a genuine issue of trustworthiness is raised, there are four straightforward criteria to apply, and a few checklists to follow, in order to assess admissibility.

These principles apply across the board to computer-generated evidence and provide a convenient framework for evaluating complex animations (reconstructions, re-creations, simulations and the like). There are also a few attendant issues raised by computer-generated evidence that should be addressed both pretrial and at trial.


There are at least four categories of frequently-proffered computer-generated evidence as to which no computer-specific foundation is usually necessary, unless the opponent raises a genuine issue as to the trustworthiness of the exhibit. As to each, the proponent's burden under Rule 104(a) is satisfied without the more elaborate foundation discussed in §§ II - IV, below, in the absence of a genuine issue as to trustworthiness.

A. Simple Demonstrative Evidence

Charts, graphs and diagrams are admissible if they are fairly accurate, are judged helpful in understanding the matters at issue, and any deficiencies are made known to the factfinder. Exhibits of this sort today are commonly computer-generated rather than drawn by hand. The test of admissibility, however, remains the same. Once a knowledgeable witness testifies that a graph, chart, diagram, or other demonstrative exhibit generated by a computer fairly and accurately portrays a relevant subject matter, the exhibit has been authenticated and may be received, without more, subject to Rule 403 (prejudice, confusion, waste of time, cumulativeness), Rule 611(a) (vesting in the trial judge discretion over the mode and order of the presentation of evidence), and, where applicable, Rule 1006 (charts, calculations and summaries permissible to present the contents of voluminous data that are independently admissible and have previously been made available to adversaries). Unless the opponent raises a genuine issue as to trustworthiness - calling into question the computerized genesis of the exhibit - no additional authentication is generally requisite.

B. Business and Public Records

Businesses and government offices generate innumerable documents by computer in ordinary course. A printout of this sort, prepared and maintained in accordance with Rule 803(6) or (8), is a "record" of the business or public office involved. Reliability and trusworthiness are said to be presumptively established by a showing that a computer printout was made in conformance with Rule 803(6) and actually relied upon in the regular course of an enterprise's activities. Computer-generated public records that satisfy Rule 803(8) are presumptively authentic under Rule 901(b)(7) (provided that they derive from a "public office where items of this nature are kept"), Rule 902(4) (certified copies of public records self-authenticating), and Rule 1005 (certified copies of public records may be offered in lieu of originals).

C. Admissions

Computer printouts associated with an adverse party may be admissions, within Rule 801(d)(2). After the proponent has offered proof that the computer output falls within one of the five types of admission catalogued in Rule 801(d)(2), it is the opponent's burden to challenge the exhibit as untrustworthy or otherwise inadmissible.

D. Non-Prejudicial Illustrative Exhibits

Since illustrative exhibits often do not go to the jury room, courts commonly employ a less rigorous standard in reviewing them. Even complex animations may, in the judge's discretion, fall within this category. However, because of the prejudicial potential of computer-generated reconstructions and re-creations, a more stringent standard of review is applied (assuming that admission is contested), regardless of whether they are nominally offered for illustrative or substantive purposes. (The four criteria to be used in deciding whether - or how much - detailed computer authentication should be required are set forth in §§ III-IV, below.)


If a genuine issue as to the trustworthiness of any computer-generated exhibit is raised, there are both hearsay and authentication issues that must be considered. As discussed below, there are two types of computerized evidence, and hearsay problems arise in connection with only one of them. Authentication issues arise in connection with both.

A. Two Types Of Computerized Evidence:

Computer-Stored Declarations vs. Computer-Generated Output

The hearsay rule applies to computerized evidence that reiterates human declarations, as opposed to evidence that does not consist of, or contain, extrajudicial assertions. Exhibits of the first sort (computer-stored declarations) are the more prevalent. They include, for example, accounting records, invoices, charts, graphs, and summaries - generally, any printouts reiterating data that has been entered into the computer. In contrast, purely computer-generated output includes, e.g., automated telephone call records, computer-enhanced photographic images, computerized test-scoring - generally, output not reiterating human declarations but simply performing programmed tasks on non-assertions.

B. Two Levels Of Hearsay

Both the entry of the data into the computer, and any underlying assertions that are so entered, must satisfy a hearsay exception or exemption.

1. Data Entry

The act of data entry is an extrajudicial statement - i.e., assertive nonverbal conduct within Rule 801(a) - as is any underlying declaration, under Rule 801(c). Data entry is usually a regularly-conducted activity within Rule 803(6) (or, in appropriate circumstances, falls within Rule 803(8) (public records exception)). It also often falls within Rule 803(1) (present sense impression exception).

The real question about the data entry function is its accuracy. This is, in substance, an issue of authenticity (see § III, infra) and should be addressed as part of the requisite authentication foundation whenever a genuine doubt as to trustworthiness has been raised. If the foundational evidence establishes that the data have been entered accurately, the hearsay objection to the data entry function should ordinarily be overruled. See also Rule 807 (residual exception).

The Electronic "Record." As previously noted (in § I), the paper or other hard-copy output of a computer may constitute a business or public "record" within Rules 803(6) and (8). At the same time, each electronic data entry contained in the computer is itself a Rule 803(6) or (8) "record." In the terminology of these Rules, each electronic entry is a "data compilation, in any form."

Implications Of Entry-Based Analysis. Consequently, if each entry has been made in conformance with Rule 803(6) or Rule 803(8), the computer-generated output satisfies the hearsay exception even if it: (a) was not printed out at or near the time of the events recorded (as long as the entries were timely made), (b) was not prepared in ordinary course (but, e.g., for trial), and (c) is not in the usual form (but, e.g., is in graphic form). If the data are simply downloaded into a printout, they do not lose their business-record character. To the extent that significant selection, correction and interpretation are involved, their reliability and authenticity may be questioned.

Trustworthiness Requirement. Rules 803(6) and (8) effectively incorporate an authentication requirement. Rule 803(6) contemplates the admission of hearsay, if its criteria are satisfied, "unless the source of information or the method or circumstances of preparation indicate lack of trustworthiness." Rule 803(8) contains substantially identical language. This trustworthiness criterion parallels the Rule 901(a) requirement of "evidence sufficient to support a finding that the matter in question is what its proponent claims." (See the discussion in §§ III - IV, below, of the extent to which detailed authentication of the computer process is required to establish trustworthiness.)

2. Underlying Data

If the underlying data that are entered into the computer are themselves hearsay declarations, they in turn must satisfy a hearsay exception or exemption under Rule 805.


A. Basic Requirements

The authentication standard is no different for computer-generated evidence than for any other. Under Rule 901(a), "The requirement of authentication ... is satisfied by evidence sufficient to support a finding that the matter in question is what its proponent claims." There is a specific illustration of sufficient authentication for computer evidence tucked into Rule 901(b)(9), and it requires only "evidence ... showing that the process or system produces an accurate result."

B. Four Primary Authentication Criteria

Four criteria are generally sufficient to assess whether, and how much, detailed computer authentication is needed in any given case:

1.Completeness Of Data.

To the extent that the computer process is dealing with known data, fewer questions are raised than if the computer is performing operations on partial data that are assumed in whole or in part (e.g., if the computer program is filling gaps in the data - using various assumptions - before it is manipulating the data).

2.Complexity Of Manipulation.

Simple addition and subtraction raise fewer questions than complex formulae.

3.Routineness Of Entire Operation.

Routineness suggests reliability. Key components are:

  • Data collection.
  • Input/processing (software)/output.
  • Computer hardware.

4.Verifiability Of Result.

Can it be tested or checked? (Compare a pie chart depicting corporate sales results or inventory (testable) vs. a sophisticated animation depicting underground pollution contamination or recreating the cause of an aircraft crash (inherently untestable).)

The weight to be given these variables will vary from case to case, but the implications are straightforward enough. More complete data, simpler manipulation, more routine processing and more verifiable results all augur against the need for elaborate, computer-specific authentication. As any of these variables tends in the opposite direction, the court must consider the magnitude of that variance and the strength of the doubt that has been raised as to the exhibit's genuineness. If more detailed authentication is appropriate, the following checklists may prove useful.

C.Detailed Computer Authentication - Checklists

To the extent that detailed authentication is warranted or advisable in the circumstances, there are three primary areas to be covered:

  • Input (getting the information into the computer),
  • Processing (doing something with the data inside the computer), and
  • Output (getting the result out of the computer). Not all three areas will necessarily be implicated in every attack on a computer-generated exhibit.

1. Input - Authentication Checklist

There are three distinct areas of potential concern with respect to input authentication: (a) the underlying data must be probative and admissible or otherwise usable; (b) the integrity of that data must be established (e.g., that all of the documents were present to be input); and (c) the data must be input properly (e.g., only once). As reflected in the following checklist, input authentication involves both hardware and software issues.

a.Underlying Data.

i. Authenticity.

ii. Relevance/Admissibility/Utility.

b.Integrity Of Input Data.

i. Completeness of source documents/data.

ii. No duplication of documents/data.

iii. No tampering with data.

iv. Input Procedures.

A.Batch controls.

B. Verification processes.

C. Input edit routines.

D. System controls.

E. Tape library handling procedures and controls.

c. Accuracy Of Input Method.

i.Proper conversion of data (machine readable).

ii. Hardware checks.


B. Capability.

C. Reliability.

iii. Software checks. Sample tests of processing of source


2. Processing - Authentication Checklist

The primary purpose of processing authentication is to show that the hardware and the software are properly functioning and including all of the appropriate data. Note that, as the following checklist highlights, there are two types of software - systems programs (which govern the operation of the computer) and application programs (which put the computer to a particular use, such as to create a balance sheet or recreate an event) - to be authenticated.


  1. Should detect errors in transmission.
  2. Should take recovery measures:

A.Correct error or

B.Alert user.


  1. Two Types.

    A.Systems Programs.

    1. Govern operation of computer.
    2. Handle:



      c.Error Recovery.

    3. Oversee application programs.

    B.Application Programs.

    1. Put computer to a particular use.

    2. Three basic types:

      a.Standard (off-the-shelf).

      b. Customized.

      c. Custom-designed.

    3. Tests governing the admissibility of expert evidence - such as Daubert - apply at the application program level to both:

    a. The scientific theory underlying the program, and

    b. Implementation of that theory in the program.

    ii.Authenticity Tests.

    1. Not erroneously programmed.

    2. Program does not introduce errors.

    3. Flags errors.

    4. Unbiased display.

      I. Successful running of benchmark data.

      II. Absence of prior problems.

      III. Popular commercial programs.

    5. Security of system

      (Absence of tampering after data input).

    I. Security of physical plant.

    II. Systems security procedure

    a. Key words.

    b. Passwords.

    c. Limited access.

    III. Computer alerts user of alteration.

    3.Output - Authentication Checklist Authentication of output largely consists of proof that the proffered exhibit is in fact the output that was described in the earlier foundational testimony. There are three principal areas:

    1. Security of output.

      Dating/signing/other procedures.

    2. Proper request.

      Output requested is same as output generated.

    3. No transmission errors.

      Ability of hardware/software to detect errors.

      Subtlety/obviousness of common errors.

      Statistical/historical experience.


    A. Animations

    Computer-generated animations and simulations raise some unique issues. At its simplest, an animation is merely a sequence of illustrations that, when filmed, videotaped or computer-generated, creates the illusion that the illustrated objects are in motion. Traditionally - because they are drawings - animations have been subjected to the fair-and-accurate-portrayal test and have been admitted, within the trial judge's discretion, generally for illustrative purposes.

    B. Simulations (Reconstructions, Re-creations) Computer-generated simulations are based on mathematical models, and particular attention must be paid to the reliability and trustworthiness of the model. A model is a set of operating assumptions - a mathematical representation of a defined set of facts, or system. To be accurate, it must produce results that are identical or very similar to those produced by the physical facts (or system) being modeled. In order to do that, the model must contain all relevant elements - and reflect all relevant interactions - that occur in the real world.

    A simulation model, in particular, is a computer program that consists of a set of assumptions about precisely what would transpire under certain clearly defined circumstances. If the simulation model works well, the result is to show the probable consequences that are predicted by the theory that underlies the equations.

    Because of the difficulty of reflecting all of the complexities of any real world system in a computer program, various simplification techniques are used. The danger is that the introduction of simplification creates the risk of invalidating the simulation that is produced.

    C.Checklist Of Authentication Issues For Computer-Generated Animations And Simulations.

    1.Factual Foundation.

    1. Sufficiency.

    2. Admissibility.

    3. Permissibility of Use (e.g., under Rule 703).

    2.Underlying Scientific Or Technical Theory.

    1. Must satisfy Daubert or any other governing test.

    2. Under Daubert:
    1. Tested?

    2. Subjected to peer review/publication?

    3. Known/potential error rate?

      Existence/maintenance of standards?

    4. Generally accepted?

    3.Detailed Computer-Evidence Foundation (§§ II-III, supra).

    4.Mathematical Model:

    1. Appropriately measures the selected factors.

    2. Factors are relevant and inclusive.

    3. Underlying mathematical formulae and simplification techniques are apt. Daubert or other governing test is satisfied (principal Daubert criteria are set forth in item 2(b), supra).

    4. Mathematical tools were correctly applied.

    5. Problem was appropriately translated into the model.


      A. Audio Narration

      Computer-generated animations are sometimes coupled with prerecorded narrations. Because any prerecorded narration is an extrajudicial statement, a hearsay exception or exemption is required. However, live testimony from the narrator - or, if a professional narrator is used, from the author of the narration - adopting the narration as true cures the hearsay objection. Rule 611(a) vests the trial judge with discretion to decide whether to permit prerecorded narration or to require live testimony or narration from the witness on the stand. The court may also exclude all or any part of the narration, and permit the remainder - or just the video - to be displayed to the jury.

      B. Limiting Instructions

      Concerns about the potential of an animation or simulation to confuse or mislead the jury can frequently be addressed in cautionary or limiting instructions. At the time of admission, the jury should be instructed (and the record in a bench trial should reflect):

      1.Purpose.The purpose for which the evidence is being received, such as:

      1. To vizualize or clarify a witness's testimony.
      2. To illustrate a litigation theory.
      3. To demonstrate scientific principles.
      4. To show results of experiments or tests.
      5. To re-create or reconstruct events at issue.

      2.Assumptions.The principal assumptions underlying the exhibit. E.g., that it is predicated on one party's versions of the facts; that the facts are in dispute; that the exhibit is no better than the assumptions on which it rests; and that it is for the jury to decide whether those assumptions are warranted. 3. Differences. Any salient differences between the exhibit and facts at issue - for example, that the exhibit does not purport to be drawn to scale or to include all (or certain specific) variables.

      C.Partial Admission

      As indicated above, exclusion of any portion of an animation - video or audio - does not necessarily render the remainder inadmissible. Exclusion of the entirety of the audio does not preclude admission of the video, in whole or in part, in the court's discretion.

      D. Pretrial Discovery And Disclosure

      Need & Authority. If a party first sees a sophisticated computer-generated exhibit when it is offered at trial, that party labors under a very serious disadvantage in attempting to mount an effective inquiry into, or challenge to,any assumptions (factual or theoretical) on which the exhibit rests, to the manner in which it has been created, and otherwise to the fairness of the evidence. To avoid unfair prejudice, pretrial discovery of computerized evidence, including the underlying computer program, is essential.

      The Federal Judicial Center's Manual for Complex Litigation Third (1995) provides (in § 21.446) that discovery into the reliability of computerized evidence, including inquiry into the accuracy of the underlying source materials, the procedures for storage and processing, and some testing of the reliability of the results obtained, should be conducted well in advance of trial.

      The mandatory disclosure provisions of the 1993 amendments to the Federal Rules of Civil Procedure are also important in this regard since they mandate pretrial exchange of exhibits to be used as "support for the opinions" of any expert, and animations are invariably offered in connection with expert testimony. As a practical matter, pretrial exchange of computerized exhibits, and discovery into underlying programs, should be assured by provisions in the pretrial order.

      Scope Of Discovery. The scope of discovery should: (1) extend into the foundational areas described in §§ II, III and IV, above, and (2) expressly include any deleted excerpts, or outtakes, from any computer-generated video or exhibit, including any prior versions of any exhibit. If there ever was a viable work-product defense to production - which is dubious in light of the good cause that the opponent could always show - it cannot likely survive the 1993 amendment to Federal Rule of Civil Procedure 26(a)(2)(B), which requires disclosure of "the data or other information considered by the witness in forming the opinions."

      E. Preview Prior To Introduction

      If for any reason a computerized exhibit has not been disclosed to all counsel prior to trial and is not to be excluded for that reason, the exhibit should be disclosed prior to introduction outside the presence of the jury and the opponent afforded a reasonable opportunity to review it. The court, too, should review the exhibit before the jury is exposed to it, to preclude potential prejudice to either side. 139567

Share this article:


Recent Articles