Expert Evidence at Trial - The Reasonable Basis Rule

Sunday, February 29, 2004 | 0

Attorneys practicing workers' compensation law in California get used to lax evidentiary rules. As an administrative hearing concerning rights that are not considered to be as substantial as liberty or justice, and where the proceeding is intended to produce results quickly (albeit, there is much dispute as to whether that goal is accomplished), the applicable burden of proof at a workers' compensation trial is "preponderance of the evidence" (Labor Code section 3202.5).

Preponderance of the evidence, as defined by 3202.5 means "such evidence as, when weighed with that opposed to it, has more convincing force and the greater probability of truth. When weighing the evidence, the test is not the relative number of witnesses, but the relative convincing force of the evidence." This test has come to mean that the Board can accept hearsay evidence if it feels that the evidence is reasonably reliable and carries with it some convincing force.

Hearsay evidence, statements of others not based on personal knowledge of the fact, event or experience of the proponent, is generally admissible in work comp proceedings. Labor Code 5708, in part, provides, "In the conduct thereof they shall not be bound by the common law or statutory rules of evidence and procedure, but may make inquiry in the manner, through oral testimony and records, which is best calculated to ascertain the substantial rights of the parties and carry out justly the spirit and provisions of this division." Labor Code 5709 further provides in part, "No order, decision, award, or rule shall be invalidated because of the admission into the record, and use as proof of any fact in dispute, of any evidence not admissible under the common law or statutory rules of evidence and procedure."

But, as a recent Court of Appeal case demonstrated, such laxity in the rules of evidence does not mean that they can be ignored, particularly when it comes to expert testimony.

The desire to promote expeditious resolution of claims led the California Legislature to declare the medical reports shall, in all but rare cases, be used in lieu of personal expert witness testimony. LC 5703. The compromise is based on several requirements before a medical report can be declared admissible as evidence: 1) it must be signed under penalty of perjury; 2) must contain certain minimum elements of information; and 3) must identify those who participated in the making of the report. (See generally LC 4628.)

The recent case, Lockheed Litigation Cases (2004 Cal.App. 4th XX, 02/02/04) provides counsel with additional guidance on the admissibility of expert medical opinions, with the caveat that an expert's opinion must have a reasonable basis behind it.

The Lockheed Litigation Cases involved 102 plaintiffs in a consolidated matter seeking damages for wrongful deaths caused by exposure to toxic chemicals. The cases had been dismissed at the trial level on the grounds that the expert opinions offered by the plaintiffs failed to meet a statistically drawn evidentiary standard such that that the incidence of disease among exposed persons is more than two times greater than that among unexposed persons.

The plaintiffs had offered the report of Dr. Daniel Teitelbaum who based his opinion on a study by the International Agency for Research Against Cancer published in 1989. The study analyzed prior epidemiological studies of painters' exposure to dozens of chemicals, including acetone, toluene, and MEK, and concluded that the painters experienced a 40 percent greater incidence of lung cancer and a 20 percent greater incidence of various other types of cancer than did the general population. The trial court ruled that this was not statistically significant to enable it to be allowed into evidence due to its lack of statistical reliability.

The Court of Appeals agreed, and offered guidance on expert evidentiary standards, stating that "that an expert opinion must be based on matter that provides a reasonable basis for the opinion."

In summary, the Lockheed Court gives us the principles for determining the evidentiary validity of medical reports:

An expert opinion has no value if its basis is unsound.

Matter that provides a reasonable basis for one opinion does not necessarily provide a reasonable basis for another opinion.

The matter relied on must provide a reasonable basis for the particular opinion offered, and that an expert opinion based on speculation or conjecture is inadmissible.

If the trial court excludes expert testimony on the ground that there is no reasonable basis for the opinion, the appellate court reviews the exclusion of evidence under the abuse of discretion standard (not whether there was an abuse of discretion).

A trial court can determine whether there is a reasonable basis for an expert opinion by examining the opinion and the matters on which the expert relies, and does not require evidence from a second level of experts in making this determination.

Though the Lockheed case is not a workers' compensation case, the applicability of the fundamental principles in Lockheed exist. The guiding principle for evidence in work comp matter is "substantial evidence". Evidence cannot be substantial unless it is based on sound scientific/medical basis.

Lax evidentiary standards in work comp trials does not mean that counsel can ignore the rules of evidence, and good lawyering means ensuring that only sound, competent evidence is presented in support of a case.

The views and opinions expressed by the author are not necessarily those of workcompcentral.com, its editors or management.