Cumulative Evidence

Example

To prove that the defendant committed fraud, the plaintiff seeks to introduce an official business document that proves the defendant’s guilt. The court decides that the evidence is admissible. The plaintiff also has a copy of the same document. If the plaintiff seeks to have it admitted, the court would likely decide that the evidence is cumulative because another identical document establishes the same information.

Case Examples

• Definition: Courts have defined cumulative evidence as “evidence which goes to prove what has already been established by other evidence.” Smith v. Sec’y of New Mexico Dep’t of Corr., 50 F.3d 801, 829 (10th Cir. 1995)
• Trial Court’s discretion: The trial court has discretion to exclude cumulative evidence to promote judicial efficiency or time management, or to avoid jury confusion. See Jewell v. Life Ins. Co. of N. Am ., 508 F.3d 1303, 1310 (10th Cir. 2007). In Jewell, the plaintiff sued for Social Security disability benefits and submitted several doctors’ letters that all said approximately the same thing. The trial judge excluded several of these letters as cumulative evidence, and the plaintiff appealed. Id. The Appeals Court affirmed the ruling of the lower court, finding that because the letters all said roughly the same thing, they constituted cumulative evidence and could therefore be excluded. Id.
• Cumulative evidence against defendants: A defendant cannot claim that he was prejudiced by cumulative evidence or the evidence was wrongfully admitted because it was cumulative unless the evidence has no pertinent information that is not covered by another document. See United States v. Otuonye, 995 F.3d 1191, 1208 (10th Cir. 2021). In Otuonye, a pharmacist was convicted of conspiracy to sell and illegally distribute controlled substances. The pharmacist appealed this conviction, stating that several of the prosecution's witnesses gave very similar testimony and that this confused the jury. Id. The Court of Appeals disagreed, finding that although the witnesses stated some similar things, each witness provided some unique testimony, and therefore their testimony was not cumulative. Id.