The tale of the “Three Little Pigs” is used to illustrate how psychiatrists use and misuse evidence. This paper refers to the different approaches of building a case the proverbial Brick House through a forensic psychiatric study. The object is to assist the jurist by presenting a picture of the case, and then intelligently persuade.

To know psychiatry well, is but one, albeit important, element of being an expert (psychiatric) witness. Disconnected from other factors, it may play a very limited and not helpful role in the establishment of a legal decision. The expert ought to know what science is, and what it is not, as well as how to apply it to specific clinical matters under legal scrutiny. It is essential to be familiar with the rules of evidence allowing or proscribing his/her participation in the fact finding process. Lastly, it is vital to clearly differentiate between the forensic and the treating roles and responsibilities of a doctor.

To be prepared and convey “science” in the expert opinion, one should have taken the preparatory steps. First, one should know the boundaries imposed by each professional’s hat: treating psychiatrist and forensic psychiatrist.

The clinical (treating) psychiatrist relies heavily on the patient’s self report of symptoms – what the patient feels, or claims to feel. As the patient’s helper, the clinician accepts such descriptions as existing, and proceeds with the treatment, which consists first on learning more about the condition that brings the patient to the office, and then eliminating those symptoms and perhaps even their cause.

As a clinician, the mental health professional is a believer of his/her patient’s clinical descriptions with the overriding goal of diagnosis and treating an illness, advocating, a priori in the patient’s affliction. There is a pro-patient stance and the utmost adherence to the confidentiality standard. Such adherence to the doctor/patient relationship does not exist in a forensic setting. This allows the forensic doctor an objectivity that is raised to levels commonly not expected from the treating doctor. All this applies to the study of direct (the individual itself) and indirect (collateral) sources of information.

There is also the assumption of worthiness and trust to and from the patient. The doctor uses medical notions and techniques designed for the treatment of such ailment.

The treating doctor runs a risk, in a court, when explaining the origin of the symptoms described by the individual based on the dare of an occurrence. It appears that the clinician is placing those complaints in a time context based on a leap of faith, (expected only of the “treating” expert, not of the “forensic” one). Nonetheless, such connection may not be there.

In the forensic role, the psychiatrist’s neutrality and objectivity is vital for him/her to be acceptable link in the fact finding process, expected to be adhered to in the professional attitude and relationship with the examinee.

Expert witnesses are admitted to testify in courts only because they have knowledge that is beyond that of the average juror. They should also be able to teach (digest) clinical concepts into impressions designed for those not versed to get the picture.

Supreme Court decision on admissibility of expert testimony are meant to maximize scientific assistance in understanding obscure areas, which are the focus of the legal inquiry, while eradicating or minimizing speculation partisanship and bias.

The expert testimony should be based on scientific principles or techniques, in order to exclude testimony based on unreliable principles. These rules of evidence evolved from Frye v. United States [293 F. 1013; 34 A.L.R. 145 (D.C. Cir., 1923)] the general acceptance rule, to Daubert v. Merrell Dow Pharmaceuticals, Inc. [509 U.S. 579 (1993), and KumhoTire Co. Ltd, v. Carmichael, [526 U.S. 137 (1999)], relevance analysis.

The general acceptance rule states a scientific principle is admissible only after it gained general acceptance in the field in which it belongs.

The relevance analysis was adopted by the United States Supreme court for the Federal courts, rejecting Frye. Many States courts are now switching from Frye to Daubert, based upon the Federal Rule of Evidence 702. On the surface it appears to be more permissive. It provides trial judges with an important tool for preventing the introduction of conjecture and junk science under the guise of expert testimony.

The Federal Rule of Evidence 702 changed the Frye test. It states, “[i]f 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 is qualified as an expert…may testify thereto in the form of an opinion or otherwise.” The Daubert Court read Rule 702 to require that an expert’s testimony must amount to “scientific knowledge” in order to be admissible.

The Daubert decision asserts that judges must base admissibility decisions on the reliability of scientific principles, i.e. Has it been tested? Does it yield accurate results? Are there standards governing the use of such principles (i.e. clear diagnostic criteria)? What is the ratio between subjective/objective analysis? Were they the focus of analysis, and publications? Are the scientific/clinical principles generally accepted by experts in the field? (included in the Frye rule). The judge conducts a searching inquiry into the reliability of scientific principles.

The 1999 Supreme Court decision Kumho Tire extended Daubert to non-scientific experts, giving the court more discretion to evaluate experts testimony, and adding that Daubert applies not only to scientific knowledge, but also to “technical” and “other specialized” knowledge.

Professionals draw from many sources of information to reach conclusion about a case. When it comes to expert testimony in court, the law allows professionals to base their testimony on the same sources of information they rely on their normal day-to-day clinical practice outside the courtroom. The expert’s training is paramount here. For example, the focus of the practice for a marriage and family therapist is typically on relationship problems between married persons and children, rather than the diagnosis of mental illness. They may bring to court “expert” testimony that involves more advocacy than expertise.

The expert witness ought to help the attorney convince the judges that the scientific and clinical principles underlying the testimony are sufficiently reliable. Daubert says that expert testimony must amount to scientific knowledge in order to be admissible. “Scientific” implies grounding in the methods and procedures of science (from the Latin science having knowledge), and “Knowledge” means more than subjective belief or unsupported speculation.