Source: https://www.jeremywrichter.com/2015/07/01/the-admissibility-of-ipse-dixit-testimony/
Timestamp: 2019-04-19 03:26:00+00:00

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Ipse Dixit testimony comprises a statement of fact by a proponent (i.e., the condition particular equipment prior to an incident occurring) that can be neither proved nor disproved by any other evidence. A trial court is well within its purview to rule as inadmissible ipse dixit evidence, because admitting ipse dixit opinion testimony that would require the court to “take a leap of faith” to rely on the proponent’s “naked assurances” that his testimony is based in fact.
For example, Tom has left a piece of construction equipment on Sam’s property. Tom was not present when his employees used the equipment to auger holes to plant trees. Sam has agreed to return Tom’s equipment to him in exchange for Tom refunding money to Sam for work that wasn’t completed by Tom. Tom then has his employees retrieve the equipment from Sam’s property. When Tom receives the equipment from Sam, he asserts that the equipment is not in proper working condition. No one else is available to offer testimony as to the equipment’s condition.
Tom claims that Sam has breached their agreement by failing to return Tom’s equipment in the condition in which it was left on Sam’s property. In support of his claim, Tom has stated as follows: “The Caterpillar excavator, auger drive, and auger were in proper working condition when I used it to auger two holes where two of the trees had been planted. It was all in good working condition at that time.” This and any other similar statements asserted by Tom may inadmissible as evidence for several reasons, one of which is that such statements are ipse dixit testimony.
The only evidence as to the condition of Tom’s equipment at the time that it was left on Sam’s property is the opinion testimony proffered by Tom. Tom was not present when the equipment was last used prior to left by Tom’s employees, and eventual retrieval of the equipment. Tom’s opinion testimony as to the condition of the equipment is inadmissible as ipse dixit. Opinion testimony is ipse dixit and inadmissible when the only connection between the conclusion and the existing data is the proponent’s own assertions.
There is nothing in the Federal Rules of Evidence that requires a trial court to admit opinion evidence that is connected to existing data only by ipse dixit. Even where a trial court’s finding regarding the inadmissibility of ipse dixit opinion testimony is outcome-determinative, the court’s ruling will not be reversed by an appellate court. The 11th Circuit has adopted the rule in Joiner that the trial judge is not required to admit opinion evidence that is connected to existing data only by ipse dixit.
The court is well within its purview to rule as inadmissible ipse dixit evidence, because admitting ipse dixit opinion testimony that would require the court to “take a leap of faith” to rely on the proponent’s “naked assurances” that his testimony is based in fact. Because the only evidence proffered by Tom as to the condition of his equipment at the time he abandoned it is his own ipse dixit testimony, which is itself not based on personal knowledge, any statements, testimony, or assertions made by or on behalf of Tom as to the condition of his equipment at the time of its abandonment are inadmissible and due to be stricken.
 See Dukes v. Georgia, 428 F. Supp. 2d 1298, 1315 (N.D. Ga.) (aff’d sub nom. Dukes v. State of Georgia, 212 F. App’x 916 (11th Cir. 2006)).
 See Guinn v. AstraZeneca Pharm. LP, 598 F. Supp. 2d 1239, 1243 (M.D. Fla. 2009) (aff’d, 602 F.3d 1245 (11th Cir. 2010)) (citing McDowell v. Brown, 392 F.3d 1283, 1300 (11th Cir.2004)).
 See generally Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997) (holding that “nothing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert. A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered.”).
 See Cook ex rel. Estate of Tessier v. Sheriff of Monroe Cnty., Fla., 402 F.3d 1092, 1107 (11th Cir. 2005).
 See Chapman v. Procter & Gamble Distrib., LLC, 766 F.3d 1296, 1305 (11th Cir. 2014) (cert. denied, 135 S. Ct. 2312 (2015)) (citing Gen. Elec. Co., 522 U.S. at 146).
 See Dukes v. Georgia, 428 F. Supp. 2d 1298, 1315 (N.D.Ga.) (aff’d sub nom. Dukes v. State of Georgia, 212 F. App’x 916 (11th Cir. 2006)).

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