Expert Testimony and The Daubert Standard of Admissibility

Expert opinions must meet the Daubert Standard of admissibility in Texas courtrooms. As such, opinions must be scientifically valid and relevant to the facts of the case. When considering whether expert opinion meets the Daubert standard, a judge must consider whether the technique or method presented has been tested and subjected to peer review, the rate of error involved in the scientific methodology, and the general acceptance among the scientific community. The “Daubert Standard” stems from the 1993 case of Daubert v. Merrell Dow Pharmaceuticals. In that case, it was argued that an anti-nausea drug, Bendectin, caused birth defects and limb deformities in the infants of women who consumed the drug while pregnant. Various experts, both scientists and doctors, testified about the science behind these limb abnormalities secondary to Bendectin exposure.

Judges have wide discretion in the admissibility of expert testimony, particularly in family law. Prior to the Daubert Standard was the Frye Standard. Many states still use Frye as the standard for admissibility. Frye focused on science that was generally accepted by the scientific community. However, Daubert refines Frye and raises the standard by requiring evidence of reliability, validity, and error rate – important concepts in scientific research.

Most therapeutic interventions do not meet the Daubert Standard. That does not mean that such therapy approaches are not effective for therapy patients. What it does mean is that therapy is a process oriented-exercise, but not prediction-oriented. The nature of admissible, forensic social science evidence suggests that the method of scientific analysis can predict human behavior on some level. It is inappropriate for therapists engaged in treatment with a client to opine about custody, visitation, or proximate cause of injury (as examples) for those clients. If an attorney suspects a therapist may be called to give such opinions without having conducted a forensic assessment, the attorney should consider a Daubert challenge. During a Daubert challenge, the attorney should press an expert witness to provide the court with the information needed to satisfy the prongs of the Daubert Standard (peer review, error rate, and general acceptance). This does not mean that therapists cannot provide valuable evidence. If an attorney wishes to call a therapist as an expert, it is important to keep in mind that therapists are technically “fact” witnesses, not expert witnesses. They can testify to diagnosis, prognosis, treatment plans, treatment compliance, and what was discussed in sessions. What is inappropriate with regards to the Daubert Standard is any predictions that a therapist might make from this information.

In family law, judges often err on the side of hearing as much information as possible in order to assess the best interest of a child, who are some of our most vulnerable citizens. However, as an attorney, being clear about what constitutes scientific admissibility can help you know what witnesses to call, what to ask them, and how to prepare for therapist testimony that might go beyond what the law intended.