§417 Experimental Evidence

• Library: Evidence Restated Deskbook (2021 Ed.)

§417 Experimental Evidence

Experimental evidence may be admitted when it is shown that an experiment was conducted under conditions substantially similar in essential particulars to the conditions prevailing at the time of the occurrence at issue.

Notes

When admissible

The Supreme Court of Missouri discussed the admissibility of experimental evidence as follows:

The law is well settled that experimental evidence is admissible when the experiment was made under conditions substantially similar in essential particulars to the conditions which prevailed at the time of the occurrence in suit, and that the conditions need not be identical. Faught v. Washam, 329 S.W.2d 588, 598 (Mo.1959); Wilcox v. St. Louis-Southwestern Railroad Co., 418 S.W.2d 15 (Mo.1967); Klaesener v. Schnucks Markets, Inc., 498 S.W.2d 555, 557 (Mo.1973). The similarities must be in those circumstances or conditions as might supposedly affect the result in question; and the degree of similarity or difference should be judged in the light of the fundamental principle that any fact should be admissible which logically tends to aid the trier in determination of the issue. Ward v. Penn Mutual Life Insurance Co., 352 S.W.2d 413, 425 (Mo.App.1961). In determining this question of sufficient similarity, a substantial measure of discretion must be accorded to the trial judge. Klaesener v. Schnucks Markets, Inc., supra; Lietz v. Snyder Manufacturing Co., 475 S.W.2d 105, 107 (Mo.1972); Lynch v. Railway Mail Association, 375 S.W.2d 216 (Mo. App.1964); Ward v. Penn Mutual Life Insurance Co., supra.

Blevins v. Cushman Motors, 551 S.W.2d 602, 609–10 (Mo. banc 1977). The court must also determine that the experimental evidence will aid the jury in deciding the issues of the case. Alcorn v. Union Pac. R.R. Co., 50 S.W.3d 226, 245 (Mo. banc 2001).

Discretion to admit or exclude

The trial court has considerable discretion when admitting or excluding the results of experiments. See Blevins v. Cushman Motors, 551 S.W.2d 602, 610 (Mo. banc 1977); State v. Starr, 676 S.W.2d 311, 313–14 (Mo. App. S.D. 1984). '"This standard of review compels the reversal of a trial court's ruling on the admission of evidence only if the court has clearly abused its discretion.'" State v. Shore, 344 S.W.3d 292, 294 (Mo. App. S.D. 2011) (quoting State v. Madorie, 156 S.W.3d 351, 355 (Mo. banc 2005)); see also §104.A of this deskbook.

Illustrative cases

The following cases illustrate the use of this evidence and the flexibility of the requirement of "substantial similarity" of conditions:

Computer-generated evidence

"Missouri courts have not established specific foundational requirements for computer-generated evidence, but review the evidence on a case-by-case basis to determine whether a sufficient foundation was laid that, if believed by the finder of fact, supports the conclusions." Alcorn v. Union Pac. R.R. Co., 50 S.W.3d 226, 245 (Mo. banc 2001) (citations omitted). In Alcorn, an adequate foundation was laid for an expert's opinion, based on a computer simulation, as to where a train was placed in emergency stop when it was shown that:

· the simulator "has been used by the National Transportation Safety Board, the Federal Railroad Safety Commission, and other government bodies";

· the simulator "had been used for training [railroad] . . . engineers and used by . . . railroads for accident investigation";

· the expert "testified as to the information necessary for a proper train simulation";

· "[t]he information in the simulator originated from a file submitted by the

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