law-expert-testimony | EXPERT WITNESSES |


“‘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.’”  Cooper
Tire & Rubber Co. v. Mendez, 204 S.W.3d 797, 800 (Tex. 2006) (quoting Tex. R. Evid. 702); see also
Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 588–89 (1993).  Expert testimony is admissible
when (1) the expert is qualified; and (2) the testimony is relevant and based on a reliable foundation.  
Mendez, 204 S.W.3d at 800.  If the expert’s scientific evidence is not reliable, it is not evidence.  Id.  
Courts must determine reliability from all of the evidence.  Merrell Dow Pharm., Inc. v. Havner, 953 S.
W.2d 706, 720 (Tex. 1997); Taber v. Roush, 316 S.W.3d 139, 147–48 (Tex. App.—Houston [14th
Dist.] 2010 no pet.).

We review the trial court’s determination under these standards for abuse of discretion.  Mendez, 204
S.W.3d at 800.  A trial court abuses its discretion when it acts without reference to any guiding rules or
principles.  Id.  Admission of expert testimony that does not meet the reliability requirement constitutes
an abuse of discretion.  Id.  Expert testimony must be based on a reliable foundation of scientific or
professional technique or principle.  Wiggs v. All Saints Health Sys., 124 S.W.3d 407, 410 (Tex. App.
—Fort Worth 2003, pet. denied) (citing E.I. du Pont de Nemours & Co. v. Robinson, 923 S.W.2d 549,
557 (Tex. 1995)).  When the expert’s underlying scientific technique or principle is unreliable, the
expert’s opinion is no more than subjective belief or unsupported speculation and is inadmissible.  Id.  
Causation opinions predicated on possibility, speculation, and surmise are no evidence.  Havner, 953
S.W.2d at 711–12.

In Robinson, the Texas Supreme Court set forth six non-exclusive factors to assist courts in
determining whether expert testimony is admissible:

1.      The extent to which the theory has been or can be tested;

2.      The extent to which the technique relies upon the subjective interpretation of the expert;

3.      Whether the theory has been subjected to peer review and/or publication;

4.      The technique’s potential rate of error;

5.      Whether the underlying theory or technique has been generally accepted as valid by the relevant
scientific community; and

6.      The non-judicial uses that have been made of the theory or technique.

Robinson, 923 S.W.2d at 557.  The Texas Supreme Court has explained that these factors cannot
always be used in assessing an expert’s reliability but concluded that “‘there must be some basis for
the opinion offered to show its reliability.’”  Mendez, 204 S.W.3d at 801 (quoting Gammill v. Jack
Williams Chevrolet, Inc., 972 S.W.2d 713, 726 (Tex. 1998)).  Under such circumstances, expert
testimony is unreliable if there is simply too great an analytical gap between the data and the opinion
proffered.  Id. at 800.  A reviewing court is not required to ignore gaps in an expert’s analysis or
assertions that are simply incorrect, and a trial court is not required to admit evidence connected to
existing data only by the expert’s ipse dixit.  Id. at 800–01.  Bald assurances of validity do not suffice.  
Havner, 953 S.W.2d at 712.  The underlying data should be independently evaluated in determining if
the opinion itself is reliable.  Id. at 713.


Simon v. D. Miller & Assoc. PLLC (Tex.App.- Houston [14th Dist.] Feb. 12, 2009)(Boyce)
legal malpractice, expert testimony required, suit within suit requirement, default judgment denied,
causality element of cause of action, no
proof of damages)
AFFIRMED: Opinion by
Justice Boyce  
Before Justices Frost, Brown and Boyce
14-07-00894-CV   Brian Simon v. D. Miller & Associates, PLLC, Timothy John Clyne, Jamilah O. Driver, and
Ryan Bradley Bormaster
Appeal from County Civil Court at Law No 3 of Harris County
Trial Court Judge:
Linda Storey