Mechanism 20
Challenging an expert for reliability
How do you exclude an unreliable expert in Texas?
By attacking the foundation rather than the conclusion. Robinson gives six non-exclusive factors — testing, subjectivity, peer review, error rate, general acceptance, and non-judicial uses. For experience-based experts the factors often do not fit, and the question becomes whether there is too great an analytical gap between the data and the opinion.
By John P. Henry · E.I. du Pont de Nemours & Co. v. Robinson, 923 S.W.2d 549 (Tex. 1995) · Reviewed 2026-08-02
The authority
[T]he party offering the expert’s testimony bears the burden to prove that the witness is qualified … The proponent must demonstrate that the expert possesses special knowledge as to the very matter on which he proposes to give an opinion.E.I. du Pont de Nemours & Co. v. Robinson, 923 S.W.2d 549, 556 (Tex. 1995)
E.I. du Pont de Nemours & Co. v. Robinson, 923 S.W.2d 549 (Tex. 1995)
When it applies
Causation opinions, damages models, standard-of-care testimony, valuation. The challenge is worth making wherever the opinion is the case — an excluded expert on a dispositive element is a no-evidence motion waiting to be filed.
How it is proved up
- Pick the right framework. Applying the six Robinson factors to a non-scientific, experience-based expert is how a good challenge gets denied; for those, the analytical-gap test is the argument.
- Take the deposition first, and take it on methodology. What did you do, what did you rely on, what did you rule out, and what would change your opinion.
- Attack the underlying data as well as the method. An unreliable foundation makes the opinion unreliable however sound the technique.
- Move in time to be heard before trial, and get a ruling on the record. An objection carried with the case is not an exclusion.
- Line up the consequence. Where the excluded testimony was the only evidence on an element, the next filing is a no-evidence motion — which is why the sequence in this catalog runs exclusion first.
What defeats it
- An expert who is genuinely qualified and whose method is accepted in the field.
- A challenge that is really a disagreement with the conclusion, which goes to weight.
- A court that admits and lets cross-examination do the work, which many prefer.
- Failing to obtain a ruling, which waives it.
Where I have used it
As the predicate for the exclusion-then-no-evidence sequence that appears elsewhere in this catalog. The order matters: the motion to strike is set and heard on a schedule that makes a continuance costly to the other side, and the dispositive motion follows.
Questions
What are the Robinson factors in Texas?
Six non-exclusive factors for expert reliability: the extent to which the theory has been tested; the extent to which it relies on the subjective interpretation of the expert; whether it has been subjected to peer review or publication; the potential rate of error; whether it has been generally accepted as valid by the relevant scientific community; and the non-judicial uses made of it.
Do the Robinson factors apply to every expert?
No. For experience-based or non-scientific experts the factors often do not fit, and Texas courts ask instead whether there is too great an analytical gap between the data relied on and the opinion offered.
Who bears the burden on an expert challenge in Texas?
The party offering the testimony bears the burden of establishing that the expert is qualified and that the opinion is relevant and reliable.