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WO

IN THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF ARIZONA

Miguel Corzo,

Plaintiff,

v. 

Maricopa County Community College 

District, et al.,

Defendants.

No. CV-15-02552-PHX-ESW

ORDER 

Pending before the Court are three Motions (Docs. 150, 153, 154) to preclude 

expert witness testimony. Plaintiff has moved to exclude Defendants’ expert witnesses 

Timothy Gay, CPA and Charles Thompson. (Docs. 150, 153). Defendants have moved 

to preclude the testimony of Plaintiff’s expert witness Mark Kelman. (Doc. 154). 

The admissibility of expert testimony is governed by Federal Rule of Evidence 

702, which provides:

If scientific, technical, or other specialized knowledge will 

assist the trier of fact to understand the evidence or to 

determine a fact in issue, a witness qualified as an expert by 

knowledge, skill, experience, training, or education, may 

testify thereto 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.

The Court has a “gatekeeping responsibility” to ensure that expert testimony has “a 
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reliable basis in the knowledge and experience of [the relevant] discipline.” Kumho Tire 

Co. Ltd. v. Carmichael, 526 U.S. 137, 149 (1999) (quoting Daubert v. Merrell Dow 

Pharm., 509 U.S. 579, 592 (1993)). The Supreme Court “heavily emphasizes that judges 

are entitled to broad discretion when discharging their gatekeeping function” related to 

the admission of expert testimony. United States v. Hankey, 203 F.3d 1160, 1168 (9th 

Cir. 2000) (citing Kumho Tire, 526 U.S. at 152). “[N]ot only must the trial court be given 

broad discretion to decide whether to admit expert testimony, it ‘must have the same kind 

of latitude in deciding how to test an expert’s reliability.’” Id. (quoting Kuhmo Tire, 526 

U.S. at 152) (emphasis in original). If expert testimony is challenged, the party 

proffering the expert testimony must show by a preponderance of the evidence that the 

expert’s testimony is admissible. Daubert, 509 U.S. at 592 n.10. 

In applying Rule 702, the Ninth Circuit “contemplates a broad conception of 

expert qualifications.” Hangarter v. Provident Life & Accident Ins. Co., 373 F.3d 998, 

1015 (9th Cir. 2004) (emphasis, internal quotation marks, and citation omitted). “Shaky 

but admissible evidence is to be attacked by cross examination, contrary evidence, and 

attention to the burden of proof, not exclusion.” Primiano v. Cook, 598 F.3d 558, 564 

(9th Cir. 2010) (citing Daubert, 509 U.S. at 596). Alternative or opposing opinions or 

tests do not “preclude the admission of the expert's testimony–they go to the weight, not 

the admissibility.” Kennedy v. Collagen Corp., 161 F.3d 1226, 1231 (9th Cir. 1998)

(emphasis in original). Further, “[d]isputes as to the strength of [an expert's] credentials, 

faults in his use of [a particular] methodology, or lack of textual authority for his opinion, 

go to the weight, not the admissibility, of his testimony.” Id. (quoting McCullock v. H.B. 

Fuller Co., 61 F.3d 1038, 1044 (2d Cir. 1995)); see also Southland Sod Farms v. Stover 

Seed Co., 108 F.3d 1134, 1142 (9th Cir. 1997) (fact that expert’s opinions were based on 

data collected by others was immaterial to determining whether opinions were 

admissible).

In Daubert, the Supreme Court enumerated a number of factors to aid the trial 

court in its gatekeeping role: (i) whether the scientific knowledge can or has been tested; 
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(ii) whether the given theory or technique has been published or subjected to peer review; 

(iii) the potential or known error rate; and (iv) whether the theory or technique has gained 

general acceptance in the pertinent field. Daubert, 509 U.S. at 592-94. The court may 

consider any or all of the Daubert factors, depending on the “particular circumstances of 

the particular case at issue.” Kumho Tire Co., 526 U.S. at 150 (“[W]e can neither rule 

out, nor rule in, for all cases and for all time the applicability of the factors mentioned 

in Daubert.”). 

The Court considers four factors to determine if expert testimony will assist the 

trier of fact: “(i) whether the expert is qualified; (ii) whether the subject matter of the 

testimony is proper for the jury's consideration; (iii) whether the testimony conforms to a 

generally accepted explanatory theory; and (iv) whether the probative value of the 

testimony outweighs its prejudicial effect.” Scott v. Ross, 140 F.3d 1275, 1285-86 (9th 

Cir. 1998) (citations omitted). 

Based on the foregoing, and after reviewing the parties’ briefing, 

IT IS ORDERED denying Plaintiff’s “Motion to Exclude Expert Witness 

Timothy Gay, CPA” (Doc. 150). 

IT IS FURTHER ORDERED denying Plaintiff’s “Motion to Exclude 

Defendants’ Expert Witness Charles Thompson” (Doc. 153). 

IT IS FURTHER ORDERED denying Defendants’ “Motion in Limine to 

Preclude the Testimony of Plaintiff’s Expert Mark Kelman” (Doc. 154). 

Dated this 10th day of October, 2018.