Demonstrations, Tests, and Experiments

The law is well settled that experimental evidence is admissible when the demonstration, test, or experiment is made under conditions that are so similar to the original conditions that a fair comparison can be made.

The trial court is vested with broad discretion in determining whether the substantial similarity standard has been satisfied.  Typically, the party not seeking to introduce such evidence will often object because the evidence will not be favorable to its case.  If the party cannot keep such evidence out, it will then usually seek to discredit the evidence.

Video Evidence

No different standard governs admission of experimental evidence that is on video. The results of video‑recorded demonstrations, tests of experiments are admissible if the conditions under which the tests were performed were so substantially similar to the conditions at issue as to afford a fair comparison.

In general, the closer the experiment gets to simulating the accident, the more similar the conditions of the experiment must be to the actual conditions in order to be introduced at trial.  Courts are sometimes reluctant to introduce video or other experimental evidence that sometimes such evidence can be highly prejudicial.

A particular danger of staged re‑creations is that there is ample room for the party proposing the evidence to alter the conditions in subtle ways that favor its own case.  If this occurs, the jury may be influenced by particular conditions that were introduced in the video, but which were not independently authenticated.

Scene‑Based Demonstrations and Tests

Video is often used in vehicular accident cases to depict what the parties could have seen at and before the time of the collision. If the recorded demonstration is conducted in a fashion substantially similar to the way in which the accident occurred — i.e., same or similar type of vehicle traveling at substantially the same speed; camera in the driver’s seat at eye level; similar conditions otherwise — the video is admissible to familiarize jurors with matters relevant on the liability issue.  That all conditions are not precisely as they were at the time of the accident is no bar to admissibility.

Demonstrating Litigation Theories

A demonstration may be recorded on video for the express purpose of illustrating the testimony of a party or expert, including his theory of the case. If it is not distorted to achieve that end, but accurately and straightforwardly portrays what it purports to depict, it is admissible.

A demonstration need not be taped under conditions identical to those in issue to be admissible; it need only be substantially similar in material respects. However, it lies within the discretion of the trial judge to determine whether the demonstration sufficiently resembles the actual event as to be fair and informative. Of course, demonstration videos that are confusing, inflammatory, and gory, those calculated to arouse sympathy or prejudice, and those which are merely cumulative, are excludable on those grounds.

Illustrating Scientific Principles

Tests and experiments may illustrate more than a litigation theory. Consider, for example, expert witnesses drawn from the natural or engineering sciences, who frequently testify to conclusions that they have reached on the basis of specific physical principles. Videos that graphically portray those principles are admissible, within the Court’s discretion, to illustrate the basis of the expert opinion. Moreover, because they are purely illustrative of principles underlying the opinion, there is no requirement of strict adherence to the facts of the case.

How May Your Case Be Impacted Through Video?

The answer to this question will depend upon the evidence uncovered from our investigation, as well as the critical aspects of your case.  When we learn more about your case, we can then make a determination of whether or how video should be used to support your case.

Call Us Today About Your Case

We provide a free, no obligation consultation so that you may learn about us, and so we may learn by your case.  At this consultation we can explain to you your options for legal recovery.  I will also explain how we will thoroughly investigate your case, hire experts, and interview witnesses and others in seeking to fully prove your case and obtain for you the full measure of damages to which you may be entitled.


16020 Swingley Ridge Rd., Suite 340
St. Louis, MO 63017

Contact Us 888.586.7041

Submission of information to us through this contact form does not create an attorney-client relationship, so please do not submit any confidential information. If we are to serve as your attorneys, all fees and the nature of our representation will be set forth in a written agreement.

Close FormPrintable Map & Info