Expert Testimony

Expert Opinion Testimony and the Standard of Appellate Review

Posted by David Adelstein on January 11, 2015
Appeal, Expert Testimony, Standard of Review / Comments Off on Expert Opinion Testimony and the Standard of Appellate Review


Previously, I discussed expert opinion testimony and the Daubert gatekeeping test employed by trial courts to determine the admissibility of the expert testimony. But, there is much more to expert opinion testimony. 

An expert witness is NOT allowed to serve as a conduit for inadmissible hearsay so that a party is using an expert witness to simply get in testimony/evidence that is otherwise inadmissible. Doctors Co. v. State, Dept. of Ins., 940 So.2d 466, 470 (Fla. 1st DCA 2006) (“The rule is well established that if an expert is called merely as a conduit to place inadmissible evidence before the jury, the trial court appropriately exercises its discretion by excluding such evidence.”); accord Tolbert v. State, 114 So.3d 291, 294 (Fla. 4th DCA 2013) (internal quotation and citation omitted) (“Although an expert may rely on hearsay in reaching the expert’s opinion, an expert’s testimony may not merely be used as a conduit for the introduction of the otherwise inadmissible evidence.”)

Moreover, an expert is NOT permitted to bolster his/her credibility on direct examination by testifying that he/she relied on communications/consultations (hearsay) with other experts in order to reach his/her expert opinion. See Linn v. Fossum, 946 So.2d 1032 (Fla. 2006). Stated differently, an expert cannot bolster his/her credibility by testifying that a treatise, article, study, or colleague (e.g., hearsay) agrees with his/her opinion before the expert has been impeached on cross-examination. See Duss v. Garcia, 80 So.3d 358 (Fla. 1st DCA 2012).

What if the trial court allows or disallows expert testimony? In other words, what if the trial court grants a motion to strike an expert (or certain expert testimony) or denies a motion to strike an expert (or certain expert testimony)? 

“The standard of [appellate] review for trial court decisions concerning the qualifications of expert witnesses and the scope of their testimony is abuse of discretion.”   County of Volusia v. Kemp, 764 So.2d 770 (Fla. 5th 2000) (reversing final judgment because trial court erred in allowing expert opinion testimony). This means that a trial court’s acceptance of expert opinion testimony or rejection of expert opinion testimony will NOT be disturbed on appeal unless the trial court abused its discretion. Doctors Co., 940 So.2d 466 (finding the trial court did not abuse its discretion in disallowing expert testimony).


Please contact David Adelstein at or (954) 361-4720 if you have questions or would like more information regarding this article. You can follow David Adelstein on Twitter @DavidAdelstein1.

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Expert Opinion Testimony and Understanding Daubert’s Gatekeeping Test

Posted by David Adelstein on January 10, 2015
Evidence, Expert Testimony / Comments Off on Expert Opinion Testimony and Understanding Daubert’s Gatekeeping Test

Expert opinion testimony

Expert opinion testimony is an important aspect of complex civil litigation. Expert testimony assists in proving or disproving liability and damages. A credible and persuasive expert can make the difference in a case and retaining experts, generating expert opinions, and the manner in which expert opinions are presented should not be taken lightly.

Regarding expert testimony, Florida Statute s. 90.702 provides:

“If scientific, technical, or other specialized knowledge will assist the trier of fact in understanding the evidence or in determining a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education may testify about it in the form of an opinion or otherwise, if:

(1) The testimony is based upon sufficient facts or data;

(2) The testimony is the product of reliable principles and methods; and

(3) The witness has applied the principles and methods reliably to the facts of the case.”

Not all expert opinion testimony is admissible. Courts are required to employ a gatekeeping function to ensure that expert opinion testimony is reliable before that testimony is admissible. This way unreliable expert testimony is not considered by the jury.



Florida courts now apply what has been referred to as the Daubert test to determine the admissibility of ALL expert testimony. See Perez v. Bell South Telecommunications, Inc., 138 So.3d 492 (Fla. 3d DCA 2014). This test arose out of the United States Supreme Court’s decision in Daubert v. Merrell Dow Phamaceuticals, Inc., 509 U.S. 579 (1993) and has been the gatekeeping test applied to expert testimony in federal courts.   This Daubert test forms the basis of a court’s gatekeeping function regarding the admissibility of RELIABLE expert opinion testimony.

How does a party offering expert opinion testimony satisfy its burden of establishing the reliability of the testimony? Parties need to know this because it is common for parties to file a (Daubert) motion attacking the reliability of another party’s expert testimony.

The Eleventh Circuit Court of Appeal explained:

“Courts must engage in a rigorous inquiry to determine whether: (1) the expert is qualified to testify competently regarding the matters he intends to address; (2) the methodology by which the expert reaches his conclusions is sufficiently reliable as determined by the sort of inquiry mandated in Daubert; and (3) the testimony assists the trier of fact, through the application of scientific, technical, or specialized expertise, to understand the evidence or to determine a fact in issue.”

 Rink v. Cheminova, Inc., 400 F.3d 1286, 1291-92 (11th Cir. 2005) (quotation omitted).



The first factor focuses on the qualifications of the expert. The expert needs to have some qualifications in order to render his/her expert opinion. Sometimes, however, parties hire experts with minimal qualifications. Federal courts have found that this goes to the expert’s credibility at trial and not the admissibility of the expert’s opinion. See Feliciano v. City of Miami Beach, 844 F.Supp.2d 1258 (S.D.Fla. 2012). This means that the other party can impeach the expert’s credibility at trial based on the expert’s minimal qualifications in order to create the appearance that the expert is not a credible or reliable witness.



The second factor focuses on the reliability of the expert’s opinion. Just because a witness is qualified to render an opinion does NOT mean the opinion is reliable. A judge has a degree of leeway in determining the reliability of the opinion by focusing on certain nonexclusive factors such as “(1) whether the expert’s methodology can be tested; (2) whether the expert’s scientific technique has been subjected to peer review and publication; (3) whether the method has a known rate of error; (4) whether the technique is generally accepted by the scientific community.” Rink, 400 F.3d at 1292.

This second factor is the crux of the Daubert test. See Fla. Stat. s. 90.702.   To this point, Florida’s Third District Court of Appeal in implementing the Daubert test as its gatekeeping function stated: “‘a key question to be answered’ in any Daubert inquiry is whether the proposed testimony qualifies as ‘scientific knowledge’ as it is understood and applied in the field of science to aid the trier of fact with information that actually can be or has been tested within the scientific method.” Perez, 138 So.3d at 498.



The third factor focuses on whether the expert testimony will assist the jury (trier of fact) in understanding an issue in the case. Thus, the expert testimony needs to be beyond the understanding of an average lay person and must not potentially confuse or mislead the jury. See U.S. v. Frazier, 387 F.3d 1244, 1262-63 (11th Cir. 2004). Also, the expert testimony must be more than what lawyers can argue in their closing arguments. Id. at 1263.


Please contact David Adelstein at or (954) 361-4720 if you have questions or would like more information regarding this article. You can follow David Adelstein on Twitter @DavidAdelstein1.

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