Federal Defense Experts

Experts in Federal Criminal Cases



The Federal Rules of Evidence (which are closely followed by similar Rules of Evidence in state courts) define an “Expert” as basically someone with sufficient knowledge, education, skill, training or experience to form an opinion. Federal Rules of Evidence, Rule 702, specifically defines an “Expert” as follows:

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

  • the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;
  • the testimony is based on sufficient facts or data;
  • the testimony is the product of reliable principles and methods; and
  • the expert has reliably applied the principles and methods to the facts of the case.

Great latitude is given both sides, prosecution and defense, in calling an Expert to testify in a federal criminal case so long as the federal courts recognize the science, principles and methods involved as valid, the Expert is qualified to offer testimony on the subject and the judge rules that the jury would find it helpful in deciding a controlling issue in the case. However, the reliability and helpfulness of proffered expert testimony is often in dispute and the courts are now considered “gatekeepers” to exclude unreliable expert testimony.

In 1993, there was a substantial refinement in the approach taken by federal courts (and, consequently, by state courts) concerning Experts in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), a United States Supreme Court Case. The “gatekeeper” function of the federal courts was affirmed as to allowing expert testimony and guidelines or standards were discussed. In other words, the Federal judge hearing the case should make some preliminary findings before allowing an Expert to testify. The Federal Judge is the gatekeeper.

The Daubert Court set forth the following considerations for a Federal court to consider in whether to allow expert testimony: (1) whether the expert’s technique or theory can be or has been tested—that is, whether the expert’s theory can be challenged in some objective sense, or whether it is instead simply a subjective, conclusory approach that cannot reasonably be assessed for reliability; (2) whether the technique or theory has been subject to peer review and publication; (3) the known or potential rate of error of the technique or theory when applied; (4) the existence and maintenance of standards and controls; and (5) whether the technique or theory has been generally accepted in the scientific community.

Subsequently, the United States Supreme Court held that these factors might also be applicable in assessing the reliability of nonscientific expert testimony, depending upon “the particular circumstances of the particular case at issue.” Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999).

The Expert does not have to have a doctorate in the subject involved or a Ph.D. in the matter of inquiry. Carl D. Haggard of The Haggard Law Firm likes to cite to judges who are questioning the “qualifications” of a particular Defense Expert that a mechanic blue-collar worker without a high school diploma who has changed tires all his life is qualified to give testimony that, in his opinion based on his extensive training and experience, the tire was not correctly mounted to the wheel – no matter that government experts with doctorates and Ph.D.’s have testified that the sidewall of the tire failed. Of course, all things being equal, you would want your Defense Expert to be addressed in court as “Doctor”.


A Defense Expert is not necessary in every case. Federal criminal cases do not always involve matters where the opinion of a Defense Expert would be admissible or even helpful to the defense. The federal government, through the Assistant US Attorney (AUSA) in charge of the prosecution is usually, almost always, expected to call one or more experts, usually beginning the Chief Investigator of the federal agency which brought the federal charges. The “Rule of Thumb” for Carl Haggard and The Haggard Law Firm in putting together the Defense Team in a particular case is whether the government and the AUSA in Charge of the prosecution is expected to call a government Expert to give an “opinion” on disputed facts or conclusions that the government wants the jury to believe in order to convict. If a critical matter is in dispute and the AUSA is expected to call a government Expert to try to convince the jury to find a Defendant guilty, then the Defense Team also needs a Defense Expert.


The answer may be surprising because what Experts charge vary greatly from case to case and from Expert to Expert. Experts who are well qualified, will work up a case and agree to present Expert Testimony favorable to the defense in court often charge a few thousand dollars to under ten thousand dollars. Obviously, the more specialized the matter of inquiry and the more work an Expert has to do, the more the Expert will charge. Expert Witness fees in specialized matters could be well into the tens of thousands of dollars. Carl Haggard and The Haggard Law Firm will seek to find an appropriate Defense Expert to recommend to the client to retain as part of the Defense Team.